Turkey's President Tayyip Erdogan said on Wednesday he will discuss with Russian President Vladimir Putin ways to protect Syrians from potential attack in the northern province of Idlib, the largest remaining Syrian rebel-held enclave.
Syria's government and allied forces backed by Russia and Iran have swiftly recaptured other rebel strongholds in the southwest and vowed to push on and recover all of the country.
Speaking to reporters in Ankara before heading for a summit of emerging market countries in South Africa, Erdogan described the situation in Deraa and Idlib - where Turkey has set up a dozen military observation posts - as troublesome.
"We will be discussing Deraa (with Russia), which is one of the most problematic issues of all. There is also the issue of Idlib, which we will discuss because in these places anything can happen at any time," he said.
"What we want is that Syrian people would be protected from these attacks and particularly the brutal attacks of some organisations in the region," Erdogan said.
Forces loyal to Syrian President Bashar al-Assad, backed by the Russian military, have captured most of the southern province of Deraa in an offensive that began in June.
Deraa city was the scene of the first major peaceful protests against Assad in March 2011 which spiralled into a war now estimated to have killed half a million people.
Erdogan has already raised the issue of Idlib with Putin in a telephone conversation in mid-July, saying an attack by the Syrian army there could destroy the Astana process, a deal struck last year with Russia and Iran to reduce fighting between insurgents and the Syrian government in de-escalation zones.
Erdogan said the avoidance of "negative developments" in Idlib was important in terms of encouraging rebel groups to attend a meeting in Astana planned for July 30-31, according to a source at the Turkish presidency.