The Syrian government is massing forces to push further into rebel-held territory in the country's north-west after seizing a key town and surrounding a Turkish military observation post, a war monitor said on Saturday.
The town of Khan Sheikhoun in the Idlib region fell on Wednesday after years under rebel control, and on Friday troops overran the countryside to the south, encircling a Turkish observation post there.
"The day after they controlled the area south of Khan Sheikhoun, regime forces are massing in the area north of it," said Rami Abdel Rahman, the head of the Britain-based Syrian Observatory for Human Rights.
They are "preparing to continue their advance towards the area of Maaret Al Numan", a town about 25 kilometres to the north, he said.
That area has come under intense Russian and regime aerial bombardment and been depleted of almost all of its residents in the past two weeks, the Observatory says.
After Khan Sheikhoun, Maaret Al Numan is the next rebel-held town on a highway running from the capital Damascus to the Syria's second city of Aleppo, which was retaken from opposition fighters in late 2016.
The Idlib region of some three million people lies on the border with Turkey. Turkish troops have been deployed at a dozen points around it in an attempt to set up a buffer zone that was part of a failed truce
brokered between Turkey and Russia last year.
Turkey's President Recep Tayyip Erdogan discussed the situation in Syria with his Russian counterpart on Friday and will visit Moscow on Tuesday for talks with Vladimir Putin, the Turkish presidency said.
Meanwhile, Turkey's attempt to create a safe zone along its border with north-eastern Syria received a boost on Saturday after the US-backed forces that control the area said they would co-operate.
Mazloum Kobani, the head of the Syrian Democratic Forces led by the Syrian Kurdish YPG militia, said his alliance would back the agreement reached between Washington and Ankara.
The US Central Command said late on Friday that the SDF – which expelled ISIS from their last patch of territory in eastern Syria in March – had destroyed outposts in the border area.
"This demonstrates SDF's commitment to support implementation of the security mechanism framework," Centcom said.
Turkey and the US have agreed to set up a joint operations centre to oversee the creation of the "safe zone" that Ankara says is necessary to protect it from the YPG, which it considers a terrorist group.
Little is known about its size or how it will work, but Ankara has said there would be observation posts and joint patrols.
