Deadly clashes erupted in southern Idlib on Friday, hours into a ceasefire deal between Russia and Turkey aimed at ending the fighting in the last opposition-held enclave in Syria.
A war monitor and an opposition source said the fighting broke out in the Jabal al-Zawiya region between Syrian regime forces and extremists of the Turkistan Islamic Party. Fifteen people were killed, the Syrian Observatory for Human Rightssaid.
Residents and opposition forces said the violence had abated elsewhere.
But the clashes underlined the fragility of Thursday's deal between Russia, which backs Bashar Assad's regime forces, and Turkey. Ankara supports opposition fighters but has less sway over hardline extremists who control large parts of Idlib.
The ceasefire aims to contain a conflict that has displaced nearly a million people in three months in northwest Syria. Turkish President Recep Tayyip Erdogan had vowed to reverse recent advances by Assad's forces in Idlib. However, Thursday's deal froze the conflict along existing front lines, cementing significant gains by Syrian government forces.
"There may be criticism but our priority was for a ceasefire and we achieved it. Some goals were not reached but that goes for both sides," a senior Turkish official said.
Several previous deals to end the fighting in Idlib have collapsed. Analysts and residents said they feared the latest ceasefire would also fizzle out as it did not address the humanitarian crisis or air protection in any detail.
The Russia-Turkey agreement appears to achieve Russia's key goal of allowing the regime to keep control of the south-north highway known as the M5. Syrian forces captured the highway's last segments in the latest offensive.
The deal also would set up a security corridor along a key east-west highway in Idlib province known as the M4. According to the ceasefire deal published in Syrian pro-regime media, Russian and Turkish troops are supposed to begin joint patrols on the M4 on March 15. Details of its operation are due to be agreed in the next week.
"This deal isn't designed to last, rather it is designed to fail - and I am afraid in the not too distant future," said Galip Dalay, IPC-Mercator fellow at the German Institute for International and Security Affairs, according to Reuters.
"Any ceasefire arrangement in Idlib, unless it has a no-fly zone dimension, is bound to fail. Deals in the past never de-escalated. They merely froze the crisis until the next escalation."
Arriving for a meeting of European Union foreign ministers in Zagreb, Dutch minister Stef Blok said the ceasefire deal should be cemented with a no-fly zone to stop any further bombing of hospitals.
Humanitarian crisis
The latest offensive in Idlib by Assad's forces, backed by Russian airstrikes, sparked what the United Nations says may be the worst humanitarian crisis yet in a war that has driven millions from their homes and killed hundreds of thousands.
Russia had repeatedly played down any talk of a refugee crisis and accused Turkey of violating international law by pouring troops and equipment into Idlib since early last month. About 60 Turkish troops have been killed in that time.
Turkey, which has the second largest army in the transatlantic NATO alliance, has tried to resist the Syrian regime advance and prevent a wave of refugees over its southern border. It already hosts 3.6 million Syrian refugees.
Russian President Vladimir Putin, standing next to his Turkish counterpart Recep Tayyip Erdogan, said on Thursday he hoped the deal "will serve as a good basis for a cessation of military activity in the Idlib de-escalation zone".
Erdogan said the sides would work together to supply aid to Syrians in need, but that Turkey retained the right to "respond to all (Syrian) regime attacks in the field."
Residents and fighters in the region said the main front lines - which have seen heavy airstrikes by Russian and Syrian jets, and intense Turkish artillery and drone strikes on regime forces - were quiet hours after the ceasefire came into effect at midnight.
‘Very tense calm’
There was only sporadic fire from machine guns, mortars and artillery by regime forces and Iranian militias on some front lines in the south of Idlib and also in the adjacent Aleppo province, they said.
"In the first hours, we are witnessing a very tense calm from all warring parties," said Ibrahim al-Idlibi, an opposition figure in touch with opposition groups on the ground. "Everyone is aware that violations by any side would be met with a response. But this a very fragile truce."
As the ceasefire was being negotiated on Thursday, Turkey staged an attack with a combat drone against Assad's forces and "neutralized" 21 Syrian regime soldiers, a term commonly used to mean killed, the Turkish Defense Ministry said. Earlier, two Turkish troops were killed by the Syrian side.
Syrian state media did not report the latest ceasefire deal.
In particular, it did not address a Turkish demand that Syrian forces withdraw to the edge of a buffer zone agreed in Sochi in 2018.
It also did not detail a "safe zone" or describe how displaced people could return to the homes they have fled to escape the Russian-backed offensive.
"No one has mentioned a safe zone or areas of withdrawal. There is no pullout, and where will the displaced go (who) would never accept going to (Assad) regime areas? What we have heard is not comforting," said Ahmad Rahhal, a former general in the Syrian regime forces who defected to the opposition.
UN Nations Secretary-General Antonio Guterres said he hoped the deal would lead to "an immediate and lasting cessation of hostilities that ensures the protection of civilians in northwest Syria, who have already endured enormous suffering," UN spokesman Stephane Dujarric said in a statement.
