The U.S. struck multiple Houthi weapons storage facilities in parts of Yemen that the Iranian-backed rebel group controls, a defense official said Wednesday evening. The strikes targeted weapons that are used to target civilian vessels in the Red Sea and Gulf of Aden, the defense official said. B-2 bombers were used to carry out the most recent strikes, which is the first time the U.S. has used that kind of aircraft during strikes against the Houthis in Yemen, a U.S. official told NBC News. The Houthis, an Irani-backed militia that has taken over part of Yemen, started launching missiles, drones and other attacks against shipping vessels in response to the war in Gaza. The Houthis have announced their support of terror group Hamas. The Red Sea has an annual $1 trillion flow of goods going through the waterway. Some shippers responded to the attacks late last year by suspending service in the Red Sea. The U.S. first launched airstrikes against Houthi weapons in January, in response to those Houthi attacks against commercial shipping. This is a developing story. Check back for updates. This story first appeared on NBCNews.com. More from NBC News: The judge handling Boeing’s plea deal asks Justice Department to explain its diversity policy Supreme Court allows Biden to implement plan to curb carbon emissions from power plants An AI-powered bot army on X spread pro-Trump and pro-GOP propaganda, research shows