The US has launched airstrikes targeting underground bunkers used by Yemen's Houthi rebels.
In a rare move, long-range B-2 stealth bombers were used against the Houthis, who have been attacking ships in the Red Sea corridor for months.
It wasn't immediately clear what damage the strikes caused but local media reported sites had been hit around Yemen's capital, Sanaa, which the group has held since 2014.
Strikes around the Houthi stronghold of Saada were also reported.
US defence secretary Lloyd Austin said the B-2 bombers targeted "five hardened underground weapons storage locations in Houthi-controlled areas of Yemen".
"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."
United States Central Command said damage assessments are underway and do not indicate civilian casualties.
The Houthis have targeted more than 80 merchant vessels with missiles and drones in the Red Sea since the war in Gaza started last October.
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Four sailors have been killed in the campaign and two vessels have been sunk.
The Houthis maintain that they target ships linked to Israel, the US or the United Kingdom in a bid to end Israel's campaign against Hamas in Gaza.
However, many of the ships attacked have little connection to the conflict, including some bound for Iran.
The Houthis also continue to launch missiles targeting Israel and have shot down a number of US military drones as well.
The rebels threatened new attacks after Israel's ground invasion of Lebanon and its killing of Hezbollah leader Hassan Nasrallah.
(c) Sky News 2024: US launches airstrikes against Houthis in Yemen
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