Marines Halt Defiant Iraqi Ship : Gulf crisis: U.S. troops drop from a helicopter onto the vessel after it ignores warning shots. No prohibited cargo is found.

DHAHRAN, Saudi Arabia —  In a new show of force aimed at ending Iraqi defiance at sea, U.S. Marines swung from helicopters to the deck of a homeward-bound Iraqi ship and forced it to halt Sunday as American fighter planes screeched overhead, military officials said.

The aerial assault off the coast of Oman marked the first time the United States has forced a boarding on a moving Iraqi ship and the first use of American warplanes in an interception.

Although U.S. forces have previously fired warning shots to intimidate Iraqi captains into stopping, they had always awaited the captain’s permission before dispatching what is usually a combined Navy-Coast Guard team to inspect the ship and its cargo.

The armed Marines met no resistance in the helicopter-borne operation against the 900-foot merchant vessel Amuriyah. But the ship had defied warning shots from an American frigate’s five-inch gun, and a Navy official said: “I’m sure (the Marines) weren’t welcome.”

The Iraqi ship was later permitted to continue to Iraq after a joint boarding party of U.S. and Australian personnel found it to be carrying no cargo prohibited by U.N. sanctions, according to a military spokesman.

The changed American tactics came a week after another Iraqi vessel ignored a barrage of warning shots and continued on its course for more than a day in a move suggesting that Iraqi captains may no longer be intimidated even by heavy naval gunfire.

U.S. commanders ordered the assault by Marines on Sunday morning, just two hours after the Iraqi ship first rejected an American order to stop. The assault suggested a new American unwillingness to permit prolonged standoffs at sea.

According to an account provided by military officials here, the Marines descended unannounced on the Iraqi vessel on ropes from a helicopter dispatched from the U.S. amphibious ship Ogden. The ship is part of a fleet carrying 10,000 Marines in the gulf region.

About the same time, two fighter planes from the U.S. carrier Independence streaked at low altitude past the Iraqi vessel half a dozen times in a display that officials here said was intended “to underscore our resolve to enforce the U.N. sanctions.”

It was unclear how the Marines forced the 157,000-ton Amuriyah to a halt. A military statement said only that the Iraqi vessel “was stopped” at 9:50 a.m. local time after the team of Marines “was inserted” by helicopter.

Military officials here said they could not disclose how many Marines had boarded the ship or how many helicopters were involved in the operation. They also declined to provide an account of what happened aboard the Iraqi vessel except to say there had been no shots fired and no casualties.

The assault was ordered after the Iraqi vessel reported that it was bound for the Iraqi port of Basra but refused to stop despite the firing of about 200 machine-gun shots across its bow by the Australian frigate Darwin and the firing of two five-inch shells by the American frigate Reasoner.

“That’s a whole lot of lead,” one U.S. military official said.

The disregard for the warning shots continued an Iraqi pattern of defiance adhered to most stubbornly last week by the Al Bahar al Arabi, which agreed to turn back to Iraq but then continued on its course for more than a day despite heavy firing across its bow.

That episode illustrated the limits of U.S. tactics that had relied principally on warning shots to persuade ships to stop and submit to a search.

It also proved somewhat embarrassing to U.S. officials who, on the basis of an initial search, announced that the ship was carrying a prohibited cargo of plywood and steel. When finally halted, the Iraqi vessel proved to be empty. Officials said the ship’s crew had apparently dumped the prohibited cargo at sea.

U.S. officials said the Iraqi ship stopped Sunday was close to Navy vessels carrying Marines and helicopters in international waters near Masirah island in the northern Arabian Sea. They indicated that the principal reason for the helicopter-borne assault was to set a new example for Iraqi captains.

“We had to make clear we mean business,” one military official said.

Also Sunday, in eastern Saudi Arabia, hundreds of troops in cowboy hats and 19th-Century uniforms witnessed a formal change of command in their division.

In a ceremony that brought a touch of the Wild West to the Saudi desert, Army Col. Harold Burch symbolically handed a cavalry flag to Col. Richard Fousek, his successor as head of the 1st Cavalry’s support unit.

Burch, of Lake Wales, Fla., broke with tradition and rode not on a horse, but on a camel.