Air strikes on a market in Syria's Al-Qaeda-held city of Idlib killed at least 21 civilians Sunday, as hundreds fled a besieged Islamic State group bastion near the Turkish border.
Five children were among those killed in the air raids on Idlib, which is held by Al-Qaeda affiliate Al-Nusra Front and its allies, the Syrian Observatory for Human Rights said.
Peace talks towards ending Syria's five-year war have stalled, with no immediate end in sight to a conflict that has killed 280,000 people.
It was not clear who carried out the Idlib strikes, but the Observatory has reported previous air raids by the regime and its Russian ally on Idlib province, which is also controlled by Al-Nusra and rebel allies.
Footage the Observatory said was filmed after the Idlib strikes showed emergency workers training water hoses on a tall building amid a haze of smoke.
In Maaret al-Numan, an area south of the provincial capital, unidentified warplanes also killed at least six civilians including a woman and her four children, the Observatory said.
Russia launched air strikes in support of the Damascus regime in September, allowing forces loyal to President Bashar al-Assad to advance against the rebels and IS.
The Britain-based Observatory relies on a network of sources inside Syria for its information.
It says it determines what aircraft carried out raids based on their location, flight patterns and the types of planes and munitions involved.
The Observatory said Russian air strikes killed 23 civilians in strikes on Idlib city on May 31, but Russia denied carrying out raids there that day.
Suspected government strikes killed at least 37 civilians in Maaret al-Numan in April, sparking condemnation from Syria's opposition amid faltering peace talks.
- Civilians flee IS bastion -
Meanwhile, hundreds of civilians escaped the IS stronghold of Manbij in nearby Aleppo province on Sunday, helped by a US-backed Kurdish-Arab alliance surrounding the town.
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Tens of thousands had been trapped inside Manbij after the alliance encircled the town on Friday in a major blow to the jihadist group controlling it.
"Around 800 civilians fled on foot towards areas held by the Syrian Democratic Forces alliance south of the town," Observatory chief Rami Abdel Rahman said.
The SDF "transported them to safer areas".
Those still inside the town were terrified by heavy air strikes in the area, Abdel Rahman said, and food was becoming scarce after the SDF alliance blocked all roads in and out.
At least 223 IS fighters and 28 SDF troops had been killed -- as well as 41 civilians in coalition air raids -- since the alliance offensive against Manbij began on May 31, according to the Observatory.
Manbij lies at the heart of the last stretch of IS-controlled territory along Turkey's border.
The siege has severed a key IS supply route that had channelled money and weapons from the Turkish border to the group's de facto Syrian capital of Raqa city.
IS has come under attack on several fronts since declaring a cross-border "caliphate" in Syria and Iraq in 2014.
Millions of people have been displaced since Syria's civil war started in 2011 with the brutal repression of anti-government protests.
Peace talks hit deadlock after the opposition walked out of negotiations in April over the escalating violence and lack of humanitarian access.
Near Damascus, regime forces dropped 44 so-called barrel bombs -- crude, unguided explosive devices -- on rebel-held Daraya, the Observatory said.
The attacks prevented for the third straight day distribution of food aid delivered on Thursday for the first time since 2012.
The Syrian opposition in exile denounced what it labelled a "vicious act".
"There is still no aid distribution and people are still holed up at home for fear of the bombing," Shadi Matar, a member of the opposition local council in Daraya, told AFP.