LONDON — A search was underway off the northwest coast of Ireland on Saturday for a U.K. Royal Fleet Auxiliary crew member who went overboard, the U.K. Ministry of Defense said.

The Irish Coast Guard received a distress call Saturday morning from an RFA vessel reporting that a crew member last seen late Friday was missing, Ireland’s Department of Transportation said.

The auxiliary fleet was assisted in the search by the Royal Navy, a coast guard plane and helicopter, an Irish Air Corps plane and three boats from the mainly volunteer Royal National Lifeboat Institution.

There was no information about the identity of the missing crew member or the circumstances around the disappearance.

The auxiliary fleet staffed by civilian sailors provides support in combat, counters piracy and helps with evacuations and disaster relief.