DUBAI, United Arab Emirates, Oct 17, (AP): US long-range B-2 stealth bombers launched airstrikes early Thursday morning targeting underground bunkers used by Yemen's Houthi rebels, officials said. It wasn't immediately clear what damage was done in the strikes.

However, there are no previous reports of the B-2 Spirit being used in the strikes targeting the Houthis, who have been attacking ships for months in the Red Sea corridor over the Israel-Hamas war in the Gaza Strip. The Houthis' al-Masirah satellite news channel reported airstrikes around Yemen's capital, Sanaa, which the group has held since 2014.

They also reported strikes around the Houthi stronghold of Saada. They offered no immediate information on damage or casualties. U.S. Defense Secretary Lloyd Austin said in a statement that the B-2 bombers targeted "five hardened underground weapons storage locations in Houthi-controlled areas of Yemen.”

The strike also appeared to be an indirect warning to Iran, the Houthis' main benefactor, which has targeted Israel with ballistic missile attacks twice over the past year. The B-2 would be used in any American attack on hardened Iranian nuclear facilities like Natanz or Fordo given it is the only aircraft in service that can drop the GBU-57, known as the "Massive Ordnance Penetrator.”

"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. Austin and the US military's Central Command offered no immediate assessment on the damage done.

However, Central Command said in a statement that initial assessments suggested no civilians had been killed. The Red Sea has become a battlefield for shippers since the Houthis began their campaign targeting ships traveling through the waterway, which once saw $1 trillion of cargo pass through it yearly.

Houthis have targeted more than 80 merchant vessels with missiles and drones since the war in Gaza started in October 2023. They have seized one vessel and sunk two in the campaign that has also killed four sailors.

Other missiles and drones have either been intercepted by a U.S.-led coalition in the Red Sea or failed to reach their targets, which have included Western military vessels. The rebels maintain that they target ships linked to Israel, the US or the United Kingdom to force an end to Israel’s campaign against Hamas in Gaza.

However, many of the ships attacked have little or no 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 U.S. military MQ-9 Reaper drones. The rebels have threatened new attacks in response to Israel's ground invasion of Lebanon and its killing of Hezbollah leader Hassan Nasrallah.

The nuclear-capable B-2, which first saw action in 1999 in the Kosovo War, is rarely used by the U.S. military in combat as each aircraft is worth some $1 billion. It has dropped bombs in Afghanistan, Iraq and Libya as well. The aircraft are based at Whiteman Air Base in Missouri and typically conduct long-range strikes from there, though some B-2s were in Australia in September.