In wording that could also be interpreted as a signal to Iran, US Defence Secretary Lloyd Austin on Wednesday said the strike was a unique demonstration of the Pentagon's ability to strike hard-to-reach facilities "no matter how deeply buried underground, hardened, or fortified".
"The employment of US Air Force B-2 Spirit long-range stealth bombers demonstrate US global strike capabilities to take action against these targets when necessary, anytime, anywhere," Austin said in a statement.
A US defence official, speaking on condition of anonymity, confirmed it was the first time a B-2 bomber was used against the Houthis.
Fears of a wider Middle East conflict have grown in the wake of Iran's October 1 missile attack as Israel weighs retaliation and battles other Iran-backed groups, including Hamas in Gaza and Lebanon's Hezbollah.
Houthi fighters in Yemen have carried out nearly 100 attacks on ships crossing the Red Sea since November and say they are acting in solidarity with Palestinians in Israel's year-long war in Gaza. They have sunk two vessels, seized another and killed at least four seafarers.
They have also fired on Israel, which has carried out strikes on Houthi targets in Yemen.
The Biden administration has been acting mostly defensively against Houthi strikes in the Red Sea, usually moving to intercept drone and missile attacks against commercial vessels and US warships.
It has also struck Houthi military infrastructure but avoided broader targets in Yemen.
The US Central Command (CENTCOM) said in a post on social media website X that its battle damage assessments were under way from the latest strike and do not indicate civilian casualties.
