An Army Black Hawk helicopter crashed off the coast of Yemen on Friday, according to a news release from U.S. Central Command.

The six service members onboard the helicopter were training approximately 20 miles off the country’s southern coast, according to the release.

Five of the service members were rescued by U.S. forces, but a search is underway for the sixth service member.

Asked if the crash involved a special forces raid, Central Command told The Associated Press that “this was a routine training event specifically for U.S. military personnel.”

“Training events such as this are routinely held by U.S. forces within a theater of operations in order to maintain their proficiency within the operating environment,” CENTCOM told the AP in a statement. “Commanders deemed this location appropriate and safe for a routine training event, considering both the operational environment and weather conditions at the time.”