TRIPOLI, Jan. 28 (Xinhua) -- Security services of Libya's Sirte, a former stronghold of Islamic State (IS) affiliates, found on Sunday a mass grave of suspected IS militants, according to a security source.

"Security services, based on reports from the city's residents, found a mass grave containing bodies likely to be of IS militants, as explosive belts and grenades were found with the buried bodies," Taha Hadid, a spokesman for the Sirte's Security Force, told Xinhua.

The task of Security Force of Sirte of the UN-backed government is to protect and secure the city from any possible attacks of remaining IS militants moving in desert and mountain areas near the city.

"The mass grave was found in the residential neighborhood 600 in the city center. Six bodies were recovered by the Libyan Red Crescent teams, and DNA samples were taken," Hadid added.

Mass graves in Sirte, some 450 km east the capital Tripoli, have been found repeatedly since the government's forces took over the city and expelled IS affiliates later in 2016.

In November and December, two mass graves were found in Sirte with dozens of bodies believed to belong to IS militants.