TRIPOLI, Dec. 24 (Xinhua) -- Libya's Interior Ministry on Monday announced discovering a mass grave containing bodies believed to be of Ethiopian Christians executed by the Islamic State (IS) militants in 2015 in the city of Sirte.

According to the ministry's Criminal Investigation Department, the mass grave has been revealed during investigations with detained IS members.

"A total of 34 bodies have been recovered and saved in the department's Unit for Unidentified Bodies. The bodies will be handed over to their families once local and international legal procedures are finalized," the department said in a statement.

On April 19, 2015, IS published a video showing the terrorists executing a group of black people who they said were "followers of the fighting Ethiopian Church."

The footage showed the militants killing the victims by shooting them in the head in a location in southern Libya, while other IS militants decapitated another group in a location in eastern Libya.

Sirte, locates some 450 km east of the capital Tripoli, had witnessed months of fighting between forces allied with the UN-backed government and the IS affiliates, which ended in December 2015 with the government forces taking over the city.