The strike targeted a military training camp for Failaq al-Sham, one of the largest Turkish-backed opposition groups in Syria.
An air strike on a rebel training camp in northwest Syria killed more than 50 people and injured almost as many, a Syrian opposition spokesman and war monitor said.
Monday’s air strike in the northwestern part of Idlib province, the last rebel enclave in Syria, targeted a military training camp for Failaq al-Sham, one of the largest Turkey-backed opposition groups in Syria, said Youssef Hammoud, a spokesman for the groups .
He added that the camp’s leaders were among those killed in an air strike in Jabal al-Dweila.
The UK-based Syrian Human Rights Observatory, which oversees the war in Syria, said the strike killed 56 fighters and injured nearly 50, adding that bailouts were under way.
The Syrian observatory suspected that the air strike was carried out by Russia, a close ally of Syrian President Bashar al-Assad in the country’s civil war.
Earlier this year, Turkey and Russia signed a ceasefire in Idlib to halt a government offensive that displaced hundreds of thousands. But that has remained shaky.
Turkey has long supported Syrian rebels in Syria. Russia has negotiated with Ankara to deploy observation teams in the rebel enclave to monitor the ceasefire.