BEIRUT (Reuters) - Air strikes believed to have been carried out by Russian jets killed at least 18 people and wounded dozens more in the town of Ariha in northwest Syria on Sunday, the Syrian Observatory for Human Rights reported.

Rami Abdulrahman, director of the Observatory, said a total of at least 60 people had been killed and wounded in the attack. The pro-opposition Orient TV reported an initial death toll of 40. Reuters could not independently verify the reports.

Officials at the Russian defense ministry could not immediately be reached for comment. The Russian air force has been conducting air strikes in support of President Bashar Assad since Sept. 30.

Ariha is located in Idlib province, which is controlled by insurgent groups including the al Qaeda-linked Nusra Front. The province is not a stronghold of the Islamic State group that controls wide areas of eastern Syria.

The Syrian military withdrew from Ariha in May as alliance of rebel groups including the Nusra Front advanced in Idlib in an offensive that resulted in the entire province falling to insurgents.