The death toll from a Russian airstrike on a courthouse run by the Syrian branch of al-Qaeda has risen to 65, a monitoring group said Sunday.
The Syrian Observatory for Human Rights said that 22 civilians were among those killed in the airstrike the previous day in the north-western town of Maarat al-Nuaman, Idlib province.
Also killed were 23 members of Syrian al-Qaeda affiliate the al-Nusra Front as well as 14 prisoners held by the group and six members of other rebel factions, the Observatory said.
Idlib is dominated by al-Nusra and other hardline Islamist rebel forces. The al-Qaeda affiliate has sought to increase its influence over civilian affairs by establishing a network of Islamic law courts.
Russia launched airstrikes in support of the Syrian army in September, but President Bashar al-Assad's overstretched forces have not so far gained much ground.
The strike comes two weeks ahead of planned talks between the Syrian government and opposition after Russia, the United States and other major powers backing both government and rebel forces mounted a push for a peace deal.
The conflict that started in 2011 has killed an estimated 250,000 people and displaced more than 11 million, according to UN figures.