A yacht racing off the coasts of California and Mexico apparently collided with a much larger vessel, killing three crew members and leaving one missing, a sailing organisation said today.

The Newport Ocean Sailing Association was hosting the 125-mile Newport, California to Ensenada, Mexico yacht race when the collision occurred off the coast near the border.

"An investigation was continuing, but it appeared the damage was not inflicted by an explosion but by a collision with a ship much larger than the 37ft vessel," association spokesman Rich Roberts said in a news release early Sunday.

Three crew members of a sailboat were found dead and a search was under way early today for a fourth, in the state's second ocean racing tragedy this month.

Coast Guard boats and two aircraft as well as Mexican navy and civilian vessels were searching for the missing crew member.

Other yachts near the Coronado Islands in Mexico reported seeing debris yesterday. Searchers in the afternoon found the bodies and debris from the Aegean, whose home port is Redondo Beach, Coast Guard Petty Officer Henry Dunphy said

Two of the dead were recovered by a civilian boat, while the third was found by a Coast Guard helicopter.

Dunphy said conditions were fine for sailing.

A total of 210 boats were registered in the 65th annual yacht race, according to the Newport Ocean Sailing Association's website.

The Coronado Islands are four small, largely uninhabited islands about 15 miles south of San Diego.