U.S. B-2 bombers and other aircraft struck five underground Houthi weapons storage locations in parts of Yemen that the Iranian-backed rebel group controls, Defense Secretary Lloyd Austin said Wednesday.
The facilities, which officials said were hardened, housed "various weapons components of types that the Houthis have used to target civilian and military vessels throughout the region," Austin said.
Houthi rebels have attacked civilian vessels in the Red Sea and the Gulf of Aden. The group was suspected in an attack in August.
The strikes were the first time the U.S. has used B-2 bombers, also known as stealth bombers, in strikes against the Houthis in Yemen, a U.S. official told NBC News.
Get Tri-state area news delivered to your inbox.> Sign up for NBC New York's News Headlines newsletter.
"This was a unique demonstration of the United States’ ability to target facilities that our adversaries seek to keep out of reach, no matter how deeply buried underground, hardened, or fortified," Austin said in a statement.
The Houthis, an Iran-backed militia that has taken over part of Yemen, started launching missiles and drones and pursuing other attacks against shipping vessels in response to the war in Gaza. The Houthis have announced their support of the terrorist group Hamas.
An annual $1 trillion flow of goods goes through the Red Sea. Some shippers responded to the attacks late last year by suspending service in the Red Sea.
U.S. & World
The U.S. first launched airstrikes against Houthi weapons in January in response to the Houthi attacks against commercial shipping.
Austin said he authorized Wednesday's strikes at the direction of President Joe Biden.
Austin said the strikes are intended "to further degrade the Houthis’ capability to continue their destabilizing behavior and to protect and defend U.S. forces and personnel in one of the world’s most critical waterways."
The Houthis seized Yemen’s capital, Sana’a, in 2014. The protracted conflict has caused extreme hardship. The United Nations has called Yemen's humanitarian crisis the largest in the world and says more than 18 million people depend on humanitarian assistance.
This story first appeared on NBCNews.com. More from NBC News: