The American military said it believes it is the first time such an undersea weapon had been used in the current conflict in the Red Sea.
The United States struck five Houthi military targets, including an undersea drone, in Houthi-controlled areas of Yemen on Saturday, the U.S. military announced on Sunday.
The use of the underwater drone is believed to have been the first time that Iran-backed Houthis had employed such a weapon since they began their campaign against ships in the Red Sea and Gulf of Aden on Oct. 23, the military’s Central Command said in a statement.
American military officials provided few details of what they called an “unmanned underwater vessel,” but the Houthis have received much of their drone and missile technology from Iran. In addition to the underwater drone, the Houthis were also using a remotely piloted boat, the statement said.
The United States struck both the surface drone and the submarine drone and launched other strikes against anti-ship missiles, the military said in its statement, but provided no precise details on the location.
Maritime drones are becoming an increasingly powerful and effective weapon. Ukraine has used sea drones to devastating effect against Russia’s Black Sea Fleet. Ukraine has deployed both drones that skim the surface of the water and those that travel underwater to attack Russian ships.
Mick Mulroy, a former Pentagon official and C.I.A. officer, said the Houthis’ use of an underwater drone was significant. He said the Houthis appeared to be adjusting their strategy.
“Unmanned surface and subsurface vessels are likely more difficult to detect and destroy than aerial drones and anti-ship missiles,” Mr. Mulroy said. “If all of these weapons systems were used against one target, it could overwhelm the ship’s defenses.”
The United States Central Command, which is overseeing operations against the Houthis, said the strikes were conducted on Saturday after determining the missiles and the drones posed a threat to both American Navy ships and commercial vessels.
In late October, the Houthis began a campaign to target commercial vessels, mostly in the Red Sea, off the coast of Yemen, saying that the attacks were in solidarity with Palestinians under attack in Gaza by Israel. The stepped-up attacks have prompted an American-led international maritime response, including a series of strikes on Houthi targets in Yemen.
The U.S. has accused Iran of supplying the Houthis and in some cases helping plan operations. However, more recently, American officials have said that Iran does not have direct control over the Houthis.