Agreement between Turkey and Russia seems to have averted offensive by pro-govt forces on rebel-held Idlib province in north west, creating opportunity to consolidate deal in Oct. Summit of Turkey, Russia and Iran – guarantors of de-escalation agreement covering Idlib and adjacent rebel-held areas – in Tehran 7 Sept appeared to end in deadlock. Turkey publicly rejected prospect of pro-govt offensive and sent reinforcements to its observation points in Syria. Turkey’s European allies and U.S. also lobbied for negotiated alternative. After bilateral summit in Russian city of Sochi 17 Sept, Turkish President Erdoğan and Russian President Putin jointly announced agreement to create by 15 Oct demilitarised zone on edge of Idlib de-escalation area to be policed by Turkish and Russian forces; Turkey to take heavy weapons from rebels in demilitarised zone by 10 Oct and remove jihadist groups from zone; Idlib’s key highways to be secured and opened for transit by year’s end. Iran and Syrian govt welcomed deal. Individuals and media outlets of jihadist alliance in Idlib region Hei’at Tahrir al-Sham voiced hostility to it and rejected disarmament. Syrian anti-aircraft system 18 Sept shot down Russian military aircraft while attempting to hit four Israeli jets that had attacked missile factory near Latakia in north west on coast, killing fifteen Russian officers; Putin blamed “tragic chain of accidents” while Israel expressed “sorrow” but vowed to continue strikes against Iranian forces in Syria. Israel 4 Sept said it had carried out over 200 airstrikes against alleged Iran-linked targets in Syria since early 2017. Moscow 24 Sept announced delivery of S-300 air defence system to Syria; U.S. national security adviser called delivery “significant escalation”. In north-eastern city of Qamishli, fighting erupted 8 Sept between regime forces holding enclave and Kurdish Asayish forces, seventeen people killed. Turkey 23 Sept said it would take steps to create “safe zones” across northern Syria, including in areas held by Syrian Kurdish fighters allied with U.S. but which Ankara considers terrorists.

After taking control of last opposition-held areas in south west, pro-govt forces intensified efforts to retake north west, raising risk of further escalation there in Sept. In north west, amid reports that govt was increasing troops in area, army 9 Aug dropped fliers in rebel-held areas of Idlib province urging people to surrender. Next day govt carried out dozens of airstrikes in Hama, Idlib and Aleppo provinces, killing at least 29 people; most intense bombing in months. UN 30 Aug called on Russia, Iran and Turkey to hold off govt campaign in north west. In south west, as pro-govt forces took last pockets of territory from Islamic State (ISIS)-affiliated militants, Jordanian army said it had shelled ISIS militants in Syria 31 July-1 Aug as they approached Jordanian border, killing some. Israel said its airstrike in Syrian-held part of Golan Heights killed seven ISIS-affiliated militants night of 1-2 Aug. Russian envoy to Syria 1 Aug reportedly said Iranian forces in Syria had withdrawn their heavy weapons at least 85km from Israeli-held Golan Heights; Israel said it was not enough, demanding Iranian-backed forces leave Syria. Iran 28 Aug said it would maintain military presence in Syria as part of cooperation agreement with Syria that Iranian defence minister signed during Damascus visit 26-27 Aug. Russia said its military police and UN peacekeepers 2 Aug began patrols in Golan Heights and that to prevent “provocations against UN posts” its military police would set up eight observation posts there, to be handed over to Syrian army once situation stable. In east, opposition Syrian Democratic Forces (SDF) backed by U.S.-led coalition continued efforts to retake ISIS-held pockets. ISIS attacked army position near Deir al-Zour city 15 Aug, twelve soldiers and five militants reportedly killed. Iraq 16 Aug said its airstrike in Syria killed ISIS militants planning attacks in Iraq. UN 13 Aug estimated up to 30,000 ISIS militants remained in Syria and Iraq, about half in each country. Syrian Democratic Council, SDF’s political wing, went to Damascus early Aug for second round of talks with govt; increase in contact has yet to yield tangible results.

Pro-govt forces backed by Russian air power pursued offensive launched late June in Daraa and Quneitra provinces in south west, forcing series of rebel surrenders and reasserting govt control up to Israeli-held Golan Heights. Pro-govt forces late July advanced on last pocket of territory held by local Islamic State (ISIS) affiliate in south-west Daraa. Amid understandings with Moscow, Israel did not intervene to obstruct govt advance, but did strike in response to incidents adjacent to or in airspace above Israeli-controlled territory: Israeli airstrike 6 July hit Syrian army post in Syria that Israel said had shelled buffer zone; Israel 12 July attacked Syrian army posts near Golan Heights after Syrian drone crossed border; Israel 23 July said it had fired missiles at two rockets fired by Syrian govt in fight against ISIS, which landed inside Syrian territory – Israel’s first use of its mid-range missile shield. Israel 24 July said it had shot down Syrian warplane that crossed into airspace over Golan Heights; Syrian govt said plane had been shot while inside Syria. Israel 23 July reportedly rejected offer by Russia to keep Iran-allied forces at least 100km from Israeli-occupied Golan Heights, stating Iranian forces should leave Syria altogether. ISIS militants 25 July carried out multiple suicide bombings in govt-held Sweida city and attacked pro-govt forces and civilians in several nearby villages, killing at least 200. In east, Syrian Democratic Forces (SDF) backed by U.S.-led coalition continued efforts to retake pockets controlled by ISIS. Delegation representing SDF and allied political bodies visited Damascus late July, opening high-profile negotiating track with govt; talks currently focused on service provision, major rifts between parties remained on core issues of security control and structure of Syrian state. Turkish President Erdoğan 14 July reportedly warned Russian President Putin that attack on Idlib province in north by pro-govt forces could abrogate Astana accord between Turkey, Russia and Iran which has limited conflict in north.

Pro-govt forces backed by Russian air power late June stepped up offensive to retake from rebels area in south west toward Jordanian border raising risk of escalation in July, as U.S. and Turkey agreed on way forward for control of Manbij in north. Govt’s campaign in south west defied U.S. warnings – reiterated 21 June – to President Assad and his Russian allies of “serious repercussions” if they violated de-escalation agreement for south west negotiated in 2017 by U.S., Russia and Jordan. But U.S. late June told Syrian rebels in south west not to expect military support from it. Upsurge in violence caused at least 45,000 people to flee; Jordan late June said it would not open its border. In east, Islamic State (ISIS) offensive on al-Bukamal near Iraqi border 8 June caused dozens of casualties among pro-govt forces, reportedly including Syrian and non-Syrian Iran-backed forces. Alleged Israeli airstrikes 17 June near al-Bukamal caused dozens more casualties among pro-govt forces; Iraqi Shia militia Popular Mobilisation Units said airstrike, for which it held U.S. responsible, killed 22 of its fighters, U.S. denied it or any anti-ISIS coalition member were involved. U.S. Sec State Pompeo and Turkish FM Çavuşoğlu 4 June signed roadmap for addressing control of Manbij in north which Syrian Democratic Forces led by Kurdish-dominated People’s Protection Units (YPG) – U.S. ally which Turkey sees as threat – took from ISIS in 2016. Both sides said agreement will see YPG cadres withdraw from town to area east of Euphrates river, but most details yet to be negotiated. In first phase, U.S. and Turkish militaries 18 June began patrols along front line separating pro-Turkish and pro-YPG forces west of Manbij city. UN-led political process saw increased activity: after govt late May submitted list of nominees for committee to be charged with rewriting constitution, UN convened meetings of Russia, Turkey and Iran in Geneva 19 June and of U.S., UK, France, Germany, Saudi Arabia and Jordan 25 June.

Israel-Iran confrontation over latter’s role in Syria escalated. Following increasingly inflammatory rhetoric and suspected Israeli strikes near Damascus 8 May, Israeli artillery struck inside Syria adjacent to Israeli-occupied Golan Heights night of 9-10 May, followed by rocket strikes into Golan Heights from Syria, which Israel blamed on Iranian Revolutionary Guards. Israel responded with its most extensive airstrikes in Syria yet in conflict, hitting, it claimed, “dozens of Iranian military targets”. Iran denied responsibility for rocket launches into Golan Heights. Damascus claimed Israeli strikes hit Syrian military sites, not Iranian assets. Govt forces continued to eliminate remaining pockets of opposition control in central Syria, by striking surrender/evacuation deals with opposition forces in eastern Qalamun region, western Rif Dimashq province, in southern Damascus and north of Homs, swelling number of displaced civilians and rebel fighters in Idlib and Turkish-dominated areas in north. Pro-govt forces took control of all areas surrounding Damascus after pushing out Islamic State (ISIS) forces from pocket in south 21 May. In north west, Turkey established twelfth and final planned military observation point ringing Idlib and adjacent rebel-held areas. East of Euphrates River, rebel Syrian Democratic Forces (SDF) backed by U.S.-led coalition resumed operations to take remaining pockets of territory held by ISIS.

U.S. President Trump late March-early April plunged U.S. Syria policy into confusion, making clear he wants to seize territory still controlled by Islamic State (ISIS) and then withdraw in next several months; top military officials pushed back, highlighting risks of hasty withdrawal. Regime forces by mid-April had taken complete control of Eastern Ghouta, last significant rebel stronghold in greater Damascus; as talks over surrender deal stalled between govt and Jaish al-Islam, only rebel group still controlling part of Eastern Ghouta, regime 7 April allegedly conducted chemical weapons attack on rebel-held Douma, killing at least 42 people. In following hours, Jaish al-Islam accepted deal to evacuate thousands of fighters and civilians to Turkish-dominated territory north of Aleppo and release captives. U.S. and allies accused regime of conducting chemical attack, regime and Russia denied, with contradictory explanations. U.S., UK and France 14 April launched coordinated missile and airstrikes on three sites in Syria allegedly associated with regime’s chemical weapons program, informing Russia beforehand. Israel 9 April attacked air base in centre, which it had identified as command-and-control site for Iranian drone that entered Israeli airspace in Feb, killing seven Iranians; Iran promised retaliation. Strikes on army bases in north 29-30 April, described by Syrian opposition as Israeli and by pro-Syrian govt website as Western, reportedly killed 38 Syrian soldiers in Hama and eighteen Iranian fighters. In north, Turkey established two more observation posts 3 and 7 April along front line between rebel-held Idlib province and regime-controlled territory, bringing total to nine and consolidating Russian-Turkish efforts to pacify north west. Infighting continued between rebel alliances Hei’at Tahrir al-Sham (HTS) and Jabhat Tahrir al-Sham (JTS): parties 7 April agreed on ceasefire for mediation, which failed and fighting resumed 15 April; HTS took several towns in southern Idlib province, but lost several in western Aleppo province. Regime forces late April bombed areas in south Damascus held by jihadists and other rebels, and prepared for expected offensive against besieged rebel enclave north of Homs.

Turkish forces took control of Kurdish-held Afrin in north west and regime military pressure forced most rebels to withdraw from their last remaining stronghold in greater Damascus. In north west, Turkish forces and allied Syrian rebels extended control in Afrin enclave, entering Afrin city 18 March after Kurdish People’s Protection Units (YPG) had withrawn, encouraging civilians to leave and vowing to continue to resist Turkish-backed forces; some rebels looted private property and YPG facilities. Unidentified assailants killed YPG leader Omar Alloush at his home in Tel Abyadh on Turkish border 15 March, Alloush had been instrumental in enhancing governance in Raqqa. Roadside bomb in Manbij 29 March killed two soldiers, one from U.S. and one from UK; negotiations between Turkey and U.S. continue over whether and how YPG should withdraw from contested city as per unimplemented 2016 U.S. promise. In Idlib area, fighting between regime and rebels remained halted due to Turkish deployment in Feb and establishment of observation points, but infighting among rebels continued. Jihadist alliance Hei’at Tahrir al-Sham (HTS), after securing support of Turkestan Islamic Party, 1 March launched counter-attack against newly formed alliance Front for the Liberation of Syria, comprising Islamist groups Ahrar al-Sham, Noureddine al-Zenki and several smaller groups; talks during 9-11 March ceasefire collapsed and fighting resumed. In greater Damascus, regime forces and Russia continued ground and air offensive against Eastern Ghouta splitting rebel-held area into three non-contiguous parts each controlled by different rebel faction; two of them, Faylaq al-Rahman and Ahrar al-Sham, struck deals with regime to withdraw to opposition-held areas in north west and rebels and families began evacuating 24 March, but third, Jaish al-Islam, end-month was negotiating deal to withdraw most of its forces to Turkey’s zone of influence north of Aleppo. Islamic State (ISIS) reportedly killed dozens of pro-regime fighters in two separate offensives, seizing T2 oil-pumping station in east and al-Qadam neighbourhood in Damascus outskirts mid-March.

Regime intensified bombing of rebel-held Damascus suburb and, with Turkey expanding and entrenching its position in north west, U.S. and Russian-aligned forces clashing in east and Israel and Iran-aligned forces in south, Feb saw marked internationalisation of conflict, increasing risk of regional escalation in March. In Damascus, regime 18 Feb escalated aerial bombardment of Eastern Ghouta; over 580 civilians reported killed 18-27 Feb and rebel shelling killed at least seventeen civilians in regime-held areas of city. UN Security Council’s 24 Feb resolution demanding 30-day countrywide ceasefire went unheeded. Russia called for daily five-hour local truces in Eastern Ghouta from 27 Feb to allow humanitarian access; pro-regime bombing and rebel retaliatory shelling continued 27 Feb, regime halted airstrikes during five-hour truce 28 Feb but resumed afterwards and launched ground offensive on enclave’s eastern edge. In north west, Turkey and allied rebels continued offensive against Kurdish-held Afrin enclave, expanding narrow zone of control along its edge. Amid negotiations between Kurds and govt over Afrin’s defence, govt-aligned forces 20 Feb entered enclave to help repel Turkish assault, but do not appear to have slowed Turkish gains. U.S. increased visible military presence in Kurdish-controlled Manbij, about 100km east of Afrin, which Turkey has repeatedly threatened to attack unless Kurdish People’s Protection Units (YPG) withdraw from city. Following mid-Feb visit to Turkey by U.S. Sec State Tillerson, U.S. and Turkey agreed to form working group to address points of contention, particularly Manbij. Regime halted offensive against rebels east of Idlib province after Turkey 5 Feb started deploying additional de-escalation control forces along front lines between govt and rebels, coordinating move with Russia and jihadist alliance Hei’at Tahrir al-Sham (HTS). Islamist group Noureddine al-Zenki 20 Feb attacked HTS in western part of Aleppo province, inflicting heavy losses late Feb. In Deir al-Zour province in east, U.S. forces 7 Feb repelled offensive by pro-regime forces across Euphrates River, which marks de-confliction line separating U.S.-backed Syrian Democratic Forces (SDF) and govt-aligned forces backed by Russia and Iran; U.S. strikes reportedly killed over 100, including many Russian mercenaries. U.S. airstrikes 25 Feb on Islamic State (ISIS)-held Al Shaafah village, Deir al-Zour, reportedly killed 25 civilians. After Iranian drone allegedly entered Israeli airspace from Syria 10 Feb, Israeli jets carried out retaliatory raid on alleged Iranian drone control site in Syria; govt anti-aircraft missile shot down returning Israeli jet; Israel launched second raid against govt and Iranian targets. Israeli PM Netanyahu 18 Feb warned Israel would “if necessary” act against Iran itself, not just its proxies.

Fighting intensified in north west as regime ramped up offensive against rebels and Turkey launched assault on area held by Kurdish People’s Protection Units (YPG) around Afrin, Aleppo province; violence looked set to escalate in Feb. After breakthrough north of Hama 28 Dec, regime made significant gains in rebel areas (mainly held by jihadist alliance Hei’at Tahrir al-Sham, HTS) in north of Hama province and south east of Idlib province, areas due to come under control of regime and allies according to Sept de-escalation agreement between Turkey, Russia and Iran. Islamic State (ISIS) exploited regime offensive, taking territory from HTS north east of Hama, and reportedly advancing into areas captured by regime. ISIS advances and counter-attacks by Free Syrian Army (FSA) rebel coalition slowed regime offensive. U.S. 13 Jan described plan to create and train 30,000-strong “border security force” in areas controlled by U.S.-backed, Kurdish YPG-led Syrian Democratic Forces (SDF), to operate along borders with Turkey and Iraq; force criticised as “terror army” by Turkey, which sees YPG as Syrian off-shoot of Kurdish Kurdistan Workers’ Party (PKK) militia in Turkey. U.S. Sec State Tillerson subsequently walked-back reference to “border security force” saying U.S. training efforts focused on countering ISIS, in line with new Syria policy announced 17 Jan aiming to stabilise areas captured from ISIS, achieve political transition and contain Iranian influence. Comments did little to assuage Ankara’s concerns; Turkey 19 Jan began bombing Kurdish-held area around Afrin and, with allied Syrian rebels, next day launched ground offensive there. Turkey 21 Jan said it intended to establish “secure zone” 30km deep from Turkish border in Afrin. Turkey 24 Jan threatened to extend offensive to Kurdish-controlled Manbij town, where U.S. forces are based. U.S. reiterated that its support for Kurdish forces within SDF alliance does not include defence of Afrin, where U.S. has no forces but Russia maintained small presence prior to Turkish attack. In capital Damascus, govt continued bombing rebel-held Eastern Ghouta; monitoring group 22 Jan accused govt of using chlorine gas in area. Latest rounds of UN-mediated talks in Vienna and Russian-backed talks in Sochi, Russia late Jan made little progress.

In north west, regime and aligned forces escalated attacks with Russian air support to take areas around Khanasser (southern Aleppo province) and Abu Dali (northern Hama province) held by jihadist alliance Hei’at Tahrir al-Sham (HTS) and other rebel groups. Cooperation increased among jihadist groups: Ahrar al-Sham joined defence against pro-regime forces 14 Dec following prisoner exchange with HTS, and HTS released several prominent figures affiliated to al-Qaeda. HTS-dominated “salvation govt” in Idlib warned aspiring opposition administration “Syrian Interim Govt” based in Turkey and Turkish-controlled areas north of Aleppo to close its offices in areas under HTS control, as part of broader HTS effort to consolidate control. In south west, fighting continued between pro-regime forces and rebels around rebel-held Beit Jinn enclave near border with Lebanon and Israeli-controlled Golan; amid regime gains, rebels and families 29 Dec began evacuating enclave under surrender deal to opposition-held areas in Idlib and Daraa. Israel increased strikes on pro-regime targets, including 1 Dec missile attack against reportedly Iranian-operated base south of Damascus. In Damascus, pro-regime forces backed by Russian airstrikes continued to intensify siege and bombardment of Eastern Ghouta suburb following offensive launched mid-Nov by rebels not party to de-escalation deal in place there; regime 26 Dec agreed to allow medical evacuations of 29 critically ill patients from besieged area in return for rebel faction Jaish al-Islam’s release of 29 detainees. In east, Kurdish-led Syrian Democratic Forces (SDF) and govt-aligned forces neared end of race along opposite sides of Euphrates River to seize oil and gas resources and population centres from Islamic State (ISIS) as both reached Iraqi border; ISIS retained control of small pockets and continued to launch small-scale attacks against pro-regime targets. Little progress made in latest round of UN-mediated talks in Geneva, which concluded 14 Dec; UN envoy said govt not attempting to enter dialogue with opposition. UN envoy 22 Dec said Iran, Turkey and Russia had set up working group on release of detainees held by govt. Some 40 rebel groups 25 Dec rejected Russia’s proposed conference on Syria in Sochi late Jan, alleging that Russia was trying to bypass Geneva process.