The men awoke in the middle of the night to the roar of warplanes.

Fear was nothing new to Fanta Ali Ahmed, who was trapped with more than 100 migrants in a rickety prison. After civil war reached his home region of Tigray in Ethiopia in 2020, he had fled along one of the world’s most dangerous smuggling routes.

He had hoped to reach Saudi Arabia, across the Red Sea. Instead, as he passed through Yemeni territory ruled by the Houthi militia, he was arrested and sent to a migrant detention center in northern Yemen.

For weeks in March and April of this year, he heard American airstrikes nearby, targeting Yemen in a campaign against the Houthis, who are backed by Iran. But this was the closest the planes had ever come.

When multiple 250-pound bombs hit the prison on April 28, tearing through the roof, Mr. Fanta fell to the ground, he recalled. At first, he thought he was the only one hurt. He later realized that he was one of the luckier ones. Ten people close to him were killed, while others were left with limbs hanging by shredded skin, he said.

“The place and everyone in it were mangled,” said Mr. Fanta, 32, who survived with two broken legs and a broken arm. “I don’t know why America bombed us.”