MANAMA, Bahrain — In a rare setback for the international anti-piracy campaign off Somalia, U.S. Navy officials today admitted that the American warship USS Haditha accidentally sank a Chinese fishing vessel just east of Somalia and then inadvertently machine-gunned the survivors.

This contradicted the Haditha's initial report, which said that it had been attacked by seven pirate skiffs and a pair of pirate-operated Mirage jets armed with Exocet missiles.

Vice Adm. Mark I. Fox, the commander of the United States 5th Fleet, spoke to reporters following reports that a fishing vessel had been "blown out of the water" by "an unusually well-armed warship that happened to be flying an American flag."

Capt. Erik King, the commander of the Haditha, claims that his ship was simply following the rules of engagement.

According to him, the Haditha originally spotted what it thought was a pirate vessel while patrolling 75 nautical miles east of Somalia.

"She was casually steaming up and down the coast with a group of armed men on board, obviously lying in wait for the next innocent ship to steam across her path," King said.

Many fishing trawlers carry armed guards while sailing through Somali waters.

When the Haditha demanded the fishing boat stop and be searched, its crew refused, claiming it was a sovereign vessel in international waters.

"Under our current rules of engagement, we're allowed to prevent any suspicious vessels from leaving the area, and that's what we proceeded to do," said King, referring to the Haditha's subsequent attack on the fishing boat with its 5 inch gun, Mark 46 torpedoes, and the Captain's 9mm sidearm, which he fired from the bridge.