Air strikes killed 19 people in a village in Syria's opposition stronghold of a residential district of a town in northwestern overnight, a rescue service there and the Syrian Observatory for Human Rights said yesterday.

The strikes pounded Maar Shureen in the northwestern Idlib province and injured 25 other people, the Britain-based Observatory said. The dead included seven children, it said.

The war monitoring group added that Syrian regime or Russian aircraft had struck the village. There was no immediate comment from the Syrian military or Moscow, which have both repeatedly said they only target militants.

The Russian Defense Ministry yesterday denied allegations that its warplanes had carried out deadly strikes. The planes of Russia's air force did not carry out flights in that area," RIA cited a defence ministry statement as saying.

The Syrian regime lost Idlib after insurgents took over the provincial capital in 2015. It has since become the only province fully under opposition control, and the most populated opposition-held part of Syria.

Thousands of civilians and fighters have poured into Idlib in the past year, bussed out of towns and cities which Syrian troops seized with the help of Russia and Iran-backed militias.

Regime forces and their allies stepped up air strikes against opposition towns in the Hama countryside and the southern part of Idlib, the opposition said last week.

The province, bordering Turkey, is part of Russian-brokered de-escalation agreements that seek to shore up ceasefires in parts of western Syria. Turkey set up observation posts in Idlib in October under a deal with Russia and Iran to reduce fighting there.

Syria has only just begun to emerge from a devastating civil war that began in early 2011 when the Assad regime cracked down on pro-democracy protests with unexpected ferocity. Since then, hundreds of thousands of people have been killed in the fighting and more than 10 million displaced, according to claims by the U.N.