Drone makes emergency landing in Pacific Ocean off San Diego

SIERRA VISTA, Ariz., Jan. 28 (UPI) -- A drone patrolling the California coast made an emergency splash landing in the Pacific Ocean after an undetermined mechanical failure, officials said.

The U.S. Customs and Border Patrol was using the unmanned Predator B to patrol the coast near Mexico when its operators determined it "would be unable to return" to its base in Sierra Vista, Ariz., the agency said in a release.

The drone went down Monday night about 20 miles southwest of San Diego and was towed to shore and the agency has grounded its other drones out of "an abundance of caution" until it determines what happened to the aircraft, the Los Angeles Times reported Tuesday.