The death toll mounts from weekslong U.S. air campaign to deter rebel group’s strikes on ships in Red Sea.

The Houthi militia, which is backed by Iran, said the attack was an American strike. The U.S. Defense Department said it was assessing the claims and took them seriously.

Yemen’s Houthis alleged that a U.S. strike hit a migrant detention center in Saada, killing 68. There was no immediate comment from U.S. Central Command.