At least 81 people, including 23 Al-Qaeda fighters, were killed in Russian strikes on a prison complex run by the jihadist group in Syria's northwest, AFP reports.

The strikes on Saturday targeted an Al-Nusra Front building near a popular market in northwestern Idlib province, according to the Syrian Observatory for Human Rights.

The complex in Maarat Al-Numan housed the group's religious court and a jail.

The dead included 23 Al-Nusra fighters and six non-jihadist rebels who were in the building.

Another 52 people -- including civilians and prisoners in the complex -- were also killed.

At least one child and two women were among the civilians killed in the strikes.