A Russian air strike killed on Saturday six civilians including a child in the embattled opposition bastion of Idlib in northwestern Syria, the Syrian Observatory for Human Rights said.
The strike hit the village of Jaballa in the south of the Idlib region, taking the lives of all six from the same family, it said.
The monitor, which relies on sources inside Syria, says it determines who carries out an air strike according to flight patterns, as well as aircraft and ammunition involved.
Observatory head Rami Abdel Rahman said it was the bloodiest such Russian air raid in two months since Moscow announced a truce for the surrounding area on August 31.
Since then, eight other civilians have been killed in Russian air strikes on different dates in the region, he said.
Bashar al-Assad's forces launched a devastating military campaign against Idlib in April, killing around 1,000 civilians and forcing more than 400,000 people to flee their homes.
But a ceasefire announced by the regime's major backer Moscow has largely held since late August, though the Observatory says skirmishes persist.