An air strike late on Tuesday hit a detention centre for migrants in the Tajoura suburb of the Libyan capital of Tripoli.
There were casualties among the migrants, said an official who works in the department to combat illegal migration that runs the centre.
The U.N. refugee agency UNHCR said on Twitter that it was “extremely concerned about … accounts of refugees and migrants deceased”.
No more details were immediately available. The nationalities of the affected migrants are not known yet.
According to the United Nations, more than 3,800 refugees and migrants remain in detention centres in Tripoli close to the areas where fighting is taking place.
Tajoura is home to several military camps of forces allied to Libya’s internationally recognized government which has been battling eastern forces trying to take Tripoli.