The death toll in an air strike on a rebel-held Syrian town overnight has climbed to 57.
The Syrian Observatory for Human Rights (SOHR) said at least 57 people were killed in the air strike, which hit a court house and prison in the town of Maarat al-Numan in Idlib province.
It identified the jets as Russian, and said the court house was operated by the al Qaeda-linked Nusra Front.
Russia has been staging air strikes in Syria in support of President Bashar al-Assad since September.
The building was struck with four missiles. The dead included 23 members of the Nusra Front, three women and at least one child, SOHR said.
Syrian officials could not immediately be reached for comment.
The strike came as a UN envoy visited Damascus to advance preparations for peace talks planned this month despite opposition misgivings.
Agreement was also reached for aid to be delivered on Monday to an opposition-held town besieged by pro-government forces where the United Nations says there have been credible reports of people dying of starvation.
The aid deal will result in humanitarian supplies being sent to the opposition-held town of Madaya at the Lebanese border, and to two villages in the northwestern province of Idlib that are blockaded by rebels.
Aid agencies have warned of widespread starvation in Madaya, where some 40,000 people are at risk.
The United Nations said on Thursday that Damascus had agreed to allow access to all three areas, but did not say when the delivery would take place.
"Both date and time have been set. Aid will go to three towns on Monday morning, all at the same time," said a source familiar with the matter. A second, pro-Syrian government source confirmed the details.