An air strike which killed at least 44 migrants at a detention centre near the Libyan capital of Tripoli could be a war crime, the UN’s human rights chief has said.

The Tripoli-based government had blamed the attack on forces associated with Khalifa Hifter, whose Libyan National Army (LNA) has been waging an offensive against rival militias in the capital of the war-torn North African country since April.

UN human rights chief Michelle Bachelet said the attack “may, depending on the precise circumstances, amount to a war crime”.

Michelle Bachelet
Michelle Bachelet has expressed concern over the air strike (Magali Girardin/Keystone via AP)

Her comments came after the UN Security Council held a closed emergency session on the airstrike in Tripoli’s Tajoura neighborhood, and Secretary-General Antonio Guterres called for an independent investigation.

Charlie Yaxley, a spokesman for the UN refugee agency, said the detention centre’s proximity to the weapons depot “made it a target for the airstrikes.”

“Coordinates of this detention centre were well-known to both sides of the conflict,” Mr Yaxley said.

“It was known that there were 600 people living inside. So there can be no excuse for this centre having been hit.”

The LNA said it was targeting a nearby military site, not the detention centre.

The attack has raised questions about the European Union’s policy of cooperating with the militias that hold migrants in crowded and squalid detention centres to prevent them from crossing the Mediterranean to seek better lives in Europe.

Most of the attack’s victims were apprehended by the Libyan coast guard, which is funded and trained by the EU to stem the flow of migrants.

The fighting for Tripoli has threatened to plunge Libya into another bout of violence on the scale of the conflict that ousted Muammar Gaddafi.