Yemen’s Houthi rebels raised the death toll Monday from an alleged U.S. airstrike on a prison holding African migrants to 68 people killed. The rebels’ Civil Defense organization separately said 47 others had been wounded in the attack.

The strike in Yemen’s Saada governorate, a stronghold for the Houthis, was the latest incident in the country’s decadelong war to kill African migrants from Ethiopia and other nations who risk crossing the nation for a chance to work in neighbouring Saudi Arabia.

At least 35 people were killed and 50 others injured in US airstrikes on a shelter for African migrants in Yemen’s northern Saada province, the Houthi group said on Monday. The Houthi-run Al-Masirah TV said the bodies of 30 more people remain missing after the strikes.