BEIRUT (AP) — Syrian opposition activists say airstrikes have struck the northwestern rebel-held city of Idlib, inflicting casualties.

The Britain-based Syrian Observatory for Human Rights says the Friday night attack struck a prison run by militants, killing at least 16 people including prisoners and prison employees. It added that women were among the dead as well.

The group, which has a network of activists around the country, said some people were killed by gunfire as prison guards chased some detainees who tried to flee after the attack.

The Local Coordination Committees, another opposition activist group, said five air raids struck the city without giving further details.

Idlib is a stronghold of Syrian insurgent groups and is regularly targeted by Syrian and Russian warplanes.