The U.S. military says it struck a Houthi underwater vessel in the Red Sea

The U.S.S. Gravely destroyer is seen in the south Red Sea on Tuesday, Feb. 13. CENTCOM said U.S. forces repelled five Houthi attacks on Saturday. (Bernat Armangue/AP)

The U.S. military says it struck an underwater vessel in the Red Sea on Saturday that was deployed by Houthi rebels in Yemen.

It was the first time U.S. forces observed the Iranian-backed rebel group using what the military called an "unmanned underwater vessel" — or UUV — since beginning a spate of attacks in the region on Oct. 23, officials added.