SAN DIEGO (AP) _ Four Navy fliers were presumed lost at sea after their electronic warfare plane failed to return from a training mission and a search proved fruitless, officials said Tuesday.

The names of the crewmen were withheld pending notification of their families, Navy spokesman Lt. Gordon Hume said.

Several pieces of debris were spottted in the search area 900 miles off the San Diego coast but they sank before they could be recovered, said Hume. The search was called off Monday evening.

The Grumman-made EA-6B ''Prowler'' took off from the aircraft carrier USS Constellation on a nighttime training exercise at 11:09 p.m. PST Sunday. It was declared overdue at 2:13 a.m. Monday, prompting a sea and air search for the twin-engine jet, Navy spokesman Lt. Cmdr. Bob Pritchard said.

The aircraft was lost in an area of open sea where there was no place to land in an emergency.

The plane was assigned to an electronic warfare squadron based at the Whidbey Island (Wash.) Naval Air Station. It was accompanying the San Diego- based Constellation on a six-month deployment to the western Pacific. The carrier left San Diego last Thursday, said Pritchard.

The EA-6B, which costs about $22 million, is intended for use by the Navy in airborne electronic warfare and carries equipment capable of jamming enemy radar, he said.