Rights group Amnesty International urged the United States on Monday to investigate possible violations of international law in a deadly strike on a migrant detention facility in rebel-held Yemen.

Last month’s attack, which prompted international alarm and was part of the US bombardment campaign against the Iran-backed Huthis, killed 68 people held at a centre for irregular migrants in Saada, the rebel authorities said at the time.

Agnes Callamard, Amnesty’s secretary-general, said that “the US attacked a well-known detention facility where the Huthis have been detaining migrants”.

The dead were all migrants from African countries, the Huthis had said.

To Callamard, “the major loss of civilian life in this attack raises serious concerns about whether the US complied with its obligations under international humanitarian law”.

“The US must conduct a prompt, independent and transparent investigation into this air strike,” she added.