The Black Hawk helicopter that crashed off the coast of Yemen Friday belonged to an elite Special Operations air regiment, a U.S. defense official said Saturday. One American service member remains missing.

The helicopter was conducting hoist training just feet above the water when it lost power and went into the sea, quickly rolling over and ejecting six aboard. Col. John J. Thomas, a spokesman for the U.S. Central Command, said ships were nearby and five of the six service members were quickly recovered. Thomas said the search and rescue efforts for the missing service member are ongoing and the incident is under investigation.

The helicopter and crew were a part of the U.S. Army’s 160th Special Operations Air Regiment and working alongside a Special Operations Task Force operating in the region, said Thomas. He added that additional military units have launched from nearby Djibouti to help with the rescue efforts.

The crash occurred around 7 p.m. local time about 20 miles off Yemen’s southern coast. The 160th Special Operations Air Regiment, or SOAR, has some of the best pilots in the U.S. military. The unit recently distinguished itself during a January 29 raid in Yemen when its helicopters flew repeatedly into heavy enemy fire to support U.S. Navy SEALs pinned down on the ground. The raid resulted in the death of the SEAL Senior Chief Petty Officer Ryan Owens. The 160th was also involved in the 2011 raid that killed Bin Laden.

The unit has had few training accidents in recent years. In 2016, a 160th Chinook helicopter experienced a hard landing in Fort Campbell, Kentucky, injuring five soldiers. In 2015, a MH-60M Black Hawk — likely the same type that went down Friday — crashed on the deck of a U.S. Navy ship near Okinawa, Japan, injuring seven.

The U.S. military maintains a small special operations base near Yemen’s port of Mukalla to facilitate an ongoing campaign targeting al-Qaeda loyalists there. The Pentagon has conducted more than 80 airstrikes in Yemen this year, officials say.

Several thousand U.S. sailors and Marines also routinely operate in the region as part of a naval amphibious ready group.

Yemen is in the midst of major humanitarian crisis fueled by civil war.

While the U.S. has remained focused on striking al-Qaeda, a coalition led by Saudi Arabia — and backed by the Pentagon — has waged a parallel war against Iranian-backed Houthi militants.

Friday’s crash comes just two days after a visit to the Saudi-Yemen border by Gen. Joseph Votel, who oversees Central Command.

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