Turkey reinforced its military presence in Syria's northwestern Idlib province on Saturday as Turkish and Russian officials held talks about the Syrian government offensive there, which has displaced more than half a million people in two months.
Turkey says the advances by Russian-backed Syrian troops and their allies threaten a fresh humanitarian disaster, driving another wave of potential refugees to its southern border, and has threatened to act if they do not pull back.
Witnesses at the border said convoys of Turkish military vehicles had been crossing into Idlib since Friday, delivering supplies before turning back to return with more.
The beefing up of Turkish forces has failed to stem the advance by Syrian government forces, which took control of a strategic town close to the provincial capital and also made gains to the east of Idlib - the last major enclave of opposition to President Bashar al-Assad.
In Ankara, officials from Turkey and Russia held three hours of apparently inconclusive talks, agreeing to meet again next week. The two countries support opposing sides in Syria's nearly nine-year civil war, but have forged a series of agreements since 2017 aimed at containing the bloodshed.
"The situation in Idlib was discussed," Turkey's foreign ministry said after the talks. "Steps that could be taken to establish peace on the ground as soon as possible and advance the political process were evaluated."
The escalation in Idlib has displaced around 600,000 people since the beginning of December, according to the United Nations, and disrupted the fragile cooperation between Russia and Turkey, which already hosts 3.6 million Syrian refugees.
Turkish President Tayyip Erdogan, who backs some of the rebels who once aimed to topple Assad, threatened this week to repel the Russian-backed Syrian forces unless they withdraw from the region by the end of the month.
Syrian government forces have pressed their advances, surrounding several Turkish observation posts. On Monday, eight Turkish military personnel were killed in shelling by Syrian government forces.
"Our checkpoints in Idlib continue their duties as usual and are capable of protecting themselves," Turkey's Defence Ministry said, adding they would respond to any new attack "in the harshest manner in accordance with legitimate defence".
The Syrian Observatory for Human Rights, a UK-based war monitor, said on Saturday that 430 Turkish military vehicles had crossed into Idlib in the last 24 hours.
Turkish forces were setting up a new post at Al-Mastoumah, on the southern approach to Idlib city, the Observatory said.
Syrian state TV broadcast live on Saturday from the strategic town of Saraqeb, located at the junction of the two main highways in Idlib that Assad seeks full control of, and lies less than 10 miles (15 km) southeast of Idlib city.
It said the army had taken full control over the town.
The military media unit of the Lebanese Shi'ite group Hezbollah, which supports Assad, said it had also taken control of Syrian government force had also taken the town of Al-Eis east of Idlib, close to the main north-south highway leading to Aleppo.