A U.S. Coast Guard cutter poured cannon fire into a Japanese ghost ship that had been drifting since the last year's tsunami, sinking the vessel in the Gulf of Alaska and eliminating the hazard it posed to shipping and the coastline.

The cutter's guns tore holes in the 164-foot (50-meter) Ryou-Un Maru on Thursday, ending its long, lonely journey across the Pacific that began when the deadly tsunami set it floating more than a year ago.

The crew pummeled the ghost ship with high-explosive ammunition, and the derelict Ryou-Un Maru soon burst into flames and began taking on water, officials said.

A huge column of smoke could be seen over the gulf. The Coast Guard warned mariners to stay away, and aviation authorities did the same for pilots.

In about four hours, the ship vanished into the water, said Chief Petty Officer Kip Wadlow in Juneau.

Officials decided to sink the ship rather than risk the chance of it running aground or endangering other vessels in the busy shipping lanes between North America and Asia.

The ship had no lights or communications system. Officials didn't know how much fuel, if any, was aboard.

The National Oceanic and Atmospheric Administration and the Environmental Protection Agency decided it was safer to sink the ship and let the fuel evaporate in the open water.

The ship was at Hokkaido, Japan, and destined for scrapping when a magnitude-9.0 earthquake that struck the country in March 2011 triggered a tsunami.

The waves dislodged the vessel and set it adrift. In total, about 5 million tons of debris was swept out to sea.

The boat did not have any cargo aboard, Coast Guard spokesman Paul Webb said. He said he didn't know who owned the Ryou-Un Maru, which had been travelling about 1 mph (1.61 kph) in recent days.

As the Coast Guard was readying to fire on the vessel, a Canadian fishing vessel, the 62-foot Bernice C, claimed salvage rights over the ghost ship in international waters.

Plans to sink it were halted so the Canadian crew could have a chance to take the stricken ship. A Canadian official with knowledge of the situation told The Associated Press that the Bernice C was unable to tow it.

In the year since the tsunami, the debris from Japan has washed up on shores across the Pacific.

In January, a half dozen large buoys suspected to be from Japanese oyster farms appeared at the top of Alaska's panhandle and may be among the first debris from the tsunami.

State health and environmental officials have said there's little need to be worried that debris landing on Alaska shores will be contaminated by radiation.

The earthquake triggered the world's worst nuclear crisis since the Chornobyl accident in 1986.