More than 20 civilians were killed in airstrikes on a town in Syria's Idlib province, according to several rights monitors. The attacks targeted a prison ran by the al-Qaida-affiliated Nusra Front militant group.
The Syrian Observatory for Human Rights has reported that airstrikes on the rebel-held town of Maarat al-Numan in the northwestern Idlib province on Saturday left nearly 60 people dead, identifying the jets responsible for the strikes as Russian.
Another non-governmental organization - the Syrian Network for Human Rights (SNHR) - reported that the airstrikes had killed 21 civilians, and were conducted by "regime warplanes."
The Observatory said that 29 militants and seven detainees were also killed in the attack, which targeted a prison and courthouse ran by the Nusra Front militant group affiliated with al-Qaida, adding that the death toll "is likely to rise."
Russia, a key ally to Syrian President Bashar al-Assad, joined the nearly five-year-old conflict in September, stating its airstrikes would target the so-called "Islamic State" (IS) militant group and other "terrorist" organizations.
However, the international community and anti-government forces have accused Moscow of intentionally targeting rebel groups in a bid to prop up the Syrian president's regime.
Saturday's attacks come as UN special envoy Staffan de Mistura met with Syrian Foreign Minister Walid al-Moallem ahead of peace talks slated for January 25.
The Syrian government told de Mistura, who has been on a regional tour to bolster support for a political solution to the conflict, that it was ready to participate in the talks, but it needed to see a list of the opposition groups that would be in attendance.
Damascus considers all groups seeking Assad's ouster as "terrorists."
The conflict in Syria erupted in March 2011 when government forces cracked down on peaceful pro-democracy protests calling for Assad to step down. More than 250,000 people have since been killed and millions have been displaced by the conflict.
ls/cmk (AP, AFP, Reuters)