"U.S forces in the region are conducting an ongoing search for one US service member who was aboard the aircraft", the military said in a statement.
A U.S. military helicopter crashed during a training exercise off the coast of Yemen Friday, U.S. Central Command reported Saturday.
"This aircraft was based and launched from an overseas location [in support of] U.S. Central Command operations", the email said, declining to name the location due to operational concerns.
Five troops who were also aboard the chopper at the time of the accident were rescued, the release said.
The crash took place during a scheduled training mission, while US forces have been conducting strikes against the al Qaeda terrorist group in the region.
The Yemen branch of al Qaeda is the most active terror network, operating in the country torn by bloody conflict between government forces and Houthi rebels, who took over the capital, Sanaa, in 2015. It has claimed responsibility for high-profile attacks in Europe and the USA, including a 2009 shooting at a Little Rock, Ark., recruiting center.
The cause of the Black Hawk helicopter's crash is unknown. USA forces have launched more than 80 airstrikes in the region since late February. Three other SEALs were wounded and a Marine MV-22 Osprey tilt-rotor aircraft was destroyed in the operation.