Turkish forces on Thursday strengthened their presence in the northern Syrian province of Idlib a day after talks with Russia failed to produce a public breakthrough and reduce tension in the region.
The two countries were on the verge of war in Idlib last year before a ceasefire in March.
Syrian regime attacks and Russian air raids on Idlib resumed this month, close to Turkish military positions in the governorate.
Turkey responded by bombing forces loyal to President Bashar Al Assad, raising the stakes as President Recep Tayyip Erdogan met Presdent Vladimir Putin in the Black Sea resort city of Sochi on Wednesday.
Idlib, a rugged rural province on the border with Turkey, has become emblematic of the internationalisation of the conflict in Syria and the shifting alliances in the decade-old conflict.
Residents said Turkish troops set up on Thursday a new fortification near a side road linking regime areas to the M4 motorway in southern Idlib.
“The new position further secures the motorway against the regime,” said, Nader Alloush, a trader in the province.
Opposition sources based in Turkey said Ankara on Wednesday sent tanks to the area as well as field artillery and reconnaissance teams.
Turkey has kept many positions its army has set up along the motorway, despite the ferocious Russian air strikes in the past few weeks near Turkish positions.
The strikes hit areas controlled by the Al Qaeda-linked militant group Hayat Tahrir Al Sham on the edge of the motorway.
The Turkish government has kept channels open with Hayat Tahrir Al Sham, sources in the Syrian opposition say, despite Ankara’s commitment to combat militancy.
Russian air strikes hit Efrin
The Russian air campaign against Idlib also affected the region of Efrin farther north.
Efrin, one of Syria's most fertile regions, is held by pro-Turkish rebels.
Turkish forces, along with their Syrian rebel proxies, captured Efrin from Kurdish militia in 2018 after a deal between Ankara and Moscow.
The deal ended Kurdish militia hopes of controlling a continuous area stretching from east to west along the long border with Turkey.
But Russia still backs the same Kurdish militia east of Idlib. With Russian support in 2016, the militia captured parts of the adjacent province of Aleppo from Sunni rebels, to the ire of Turkey.
The Kurdish militia, called People Protection Units, are linked to the Turkish Kurdistan Workers Party (PKK), which Turkey, the US and the EU regard as a terrorist organisation.
The deal in March 2020 between Russia and Turkey allowed the Assad regime to capture some strategic areas in Idlib though the bulk of the governorate remained under anti-Assad forces.
In the weeks before the ceasefire, the two countries came close to war, with Russia supporting the regime’s offensive on Idlib with aerial bombing. Pro-Iranian Shiite militia also fought on the side of the regime.
Tension skyrocketed when a regime strike killed 33 Turkish soldiers in Idlib in February 2020.
Turkey retaliated with artillery and drone attacks, killing dozens of armed Assad loyalists.
Jabal Al Zawiya
The Russian strikes this month focused on the Jabal Al Zawiya region, Idlib’s most rugged region.
The area, north of the M4, is a command base for Hayat Tahrir Al Sham, opposition figures in Amman say.
The motorway links the city of Aleppo to other regime-controlled areas on the coast.
It fell under Turkish control after Russia pulled out of patrolling it jointly with the Turkish military in the summer of 2020, citing the possibility of militant attacks.
Turkey responded to the latest Russian-backed regime offensive in Idlib by shelling regime positions and sending significant reinforcements into the governorate.
Almost four million people live in Idlib. Most are Sunni civilians who fled to Idlib following the crackdown on the Syrian revolt in 2011 and during the ensuing civil war.
The revolt occurred in opposition to five decades of rule by the Assad family - members of the Alawite sect, which has dominated Syria since mostly Alawite officers took power in the 1963 coup.
Idlib and other rural Sunni governorates make up the reservoir of anti-Assad fighters.
But the 2015 Russian intervention restored significant areas of Syria to the regime. The anti-Assad forces that are left are mainly Al Qaeda-linked militants or Turkish proxies in Efrin and other areas of northern Syria.
Mr Erdogan said after he met Mr Putin on Wednesday that Turkey is committed to the March 2020 ceasefire and to “clearing radical elements” on the M4.
But Mr Erdogan added that Turkey expects its partners to do the same, vowing to keep up diplomatic and security channels with Russia in pursuit of de-escalation.