American military helicopters came under fire from Iranian-backed Houthi fighters in the Red Sea on Sunday morning and shot back, sinking three Houthi boats and killing those aboard, U.S. Central Command said.

The episode occurred after a commercial container ship was attacked by Houthi fighters in small boats and issued a distress call, prompting U.S. Navy helicopters to respond, the military said.

“In the process of issuing verbal calls to the small boats, the small boats fired upon the U.S. helicopters with crew-served weapons and small arms,” Central Command said in a statement on social media. “The U.S. Navy helicopters returned fire in self-defense, sinking three of the four small boats, and killing the crews.”

It was the latest and perhaps deadliest such incident involving the Houthis, who control a large swath of northern Yemen, since Israel went to war with Hamas on Oct. 7.