TRIPOLI, Dec. 21 (Xinhua) -- Security agencies in the Libyan city of Sirte on Thursday found a mass grave containing dozens of bodies, an official said.

"A security force went to al-Manara neighborhood and inspected the reported site, where a mass grave containing the remains of dozens of bodies was found," Taha Hadid, the spokesman for Sirte's security force, told Xinhua.

The bodies are believed to be of Islamic State (IS) militants, Hadid said.

Al-Manara is one of the last IS-held strongholds during its war against the government forces in 2015.

As soon as the weather improves in the next few days, the Red Crescent teams will recover the remains of the bodies and take DNA samples, the spokesman said.

In December 2015, forces allied with UN-backed Libyan government defeated IS affiliates and expelled them from Sirte, some 450 km east of the capital Tripoli.