Russian airstrikes reportedly killed at least 57 people and injured 40 others in Northwest Syria's Maarat al-Nu'man town on Saturday.

The Syrian Observatory for Human Rights said at least 21 civilians, 29 militants and seven detainees were killed in the strikes, Channel News Asia reported. Three women and one child are among the deceased, according to Reuters.

"The civil defense activists have so far pulled some 40 wounded people from the rubble. Some of them are seriously injured and suffer critical conditions," spokesperson of the Idlib Documentation Center Luay Hamdan told ARA News.

The observatory said the jets that carried out airstrikes on a court house and jail in Idlib province's Maarat al-Nu'man town belonged to Russia. The complex was hit by four missiles.

"The first floor of the court was targeted in addition to a prison," Anas Maarawi, a media activist in Idlib, told Al Jazeera.

The court was "operated" by the al Nusra Front – the Syrian branch of al Qaeda, which has been fighting against the Syrian forces in the country. Russia has been carrying out air strikes against the Islamist extremist groups in the Middle Eastern country since September.

Russians conducted the strikes even as UN special envoy for Syria Steffan de Mistura was in Damascus on Saturday for peace talks. The office of Mistura said the meeting was fruitful.

"The Special Envoy is looking forward to the active participation of relevant parties in the Geneva talks. He will be continuing his consultations in the region," Reuters quoted the office's statement as saying.