The foreign backed militant forces launched an attack on the army-controlled prison on Wednesday night, in the heaviest fighting for the jail in months, said the Syrian Observatory for Human Rights.

The military responded to the assault by firing a barrage of shells in the area around the prison.

After midnight, "the intensity of the fighting decreased between the army and members of the Al-Qaeda-linked Al-Nusra Front and another militant faction Ahrar al-Sham," it said in a statement.

The Observatory added that the clashes did not reach the buildings holding thousands of prisoners, mostly common criminals but also militants.

The jail, located on the northern outskirts of Aleppo, the commercial capital of Syria before a bloody uprising erupted in March 2011, has been besieged by militants since April.

In other development, Syrian government forces have recaptured the strategic town of al-Bweida, south of the capital, Damascus.

On Wednesday, Syrian forces took control of the town after pushing out foreign-backed militants and destroying their equipment.

The operation was part of a larger campaign launched several months ago to clear the southern countryside of Damascus from militants.

Also on Wednesday, fighting was reported between Syrian forces and militants near the holy shrine of Hazrat Zaynab (AS), and in the Hojeira district of south Damascus.

NJF/NJF