Not less than 40 people have lost their lives after an air strike late on Tuesday hit a detention centre for migrants in the Tajoura suburb of the Libyan capital of Tripoli.
Some 130 people were injured at the centre, which the UN-backed government says was hit by an air strike.
Ghassan Salamé said the attack, apparently carried out by forces loyal to the warlord Khalifa Haftar, “clearly could constitute a war crime, as it killed by surprise innocent people whose dire conditions forced them to be in that shelter”.
Most of the dead are believed to be Africans held in detention after attempting to reach Europe on clandestine sea crossings from Libya.
Salamé added: “The absurdity of this ongoing war today has led this odious bloody carnage to its most hideous and most tragic consequences.”
The Africa Union also issued a statement calling for an inquiry into responsibility for the attack.
It is the highest publicly reported toll of an airstrike or shelling since eastern forces loyal to Haftar launched an offensive three months ago with ground troops and aircraft to take the capital held by the internationally recognised government.
NGOs receiving voice messages from the detention centre claimed the death toll was higher, and accused Europe of ignoring warnings about the threat posed to the detention centres by Haftar’s repeated air raids in the city over the past two months.
Around 120 people are reported to have been held in the hangar, which took a direct hit,, while more than 600 people, including children, were inside detention centre complex.
The UN refugee agency, UNHCR, said it was “extremely concerned” at news of the attack, but there would be questions as to why detainees had not been moved by the agency given previous raids close to the centre.