An armed Coast Guard cutter chased a Taiwanese fishing vessel, suspected of illegal fishing in the North Pacific, for 600 miles and was prepared to board the ship looking for evidence, the Coast Guard said.

The 378-foot, high endurance cutter Jarvis encountered the Tyi Yang No. 1 south of Alaska's Aleutian Islands late Sunday, and the Taiwanese ship took off away from the Coast Guard, said Greg Robinson, spokesman in Juneau, Alaska.For three days, through bad weather, over 600 miles of international waters and awaiting a diplomatic OK for a high seas law enforcement action, the Honolulu-based Jarvis pursued the Tyi Yang.

Late Wednesday night, Robinson reported that the U.S. State Department received permission from Taiwan to stop the Tyi Yang and board it. The Taiwanese government ordered the vessel owners to cooperate with the Coast Guard, Robinson said.

There was no immediate word whether the fleeing vessel would stop and permit a Coast Guard boarding party to inspect the ship, but Robinson said the cutter would exhaust non-violent attempts to stop the ship before making it clear to the captain what other means the Jarvis had at its disposal.

However, Robinson said he expected a peaceful boarding Thursday and then a two-day escorted trip back to where the Tyi Yang abandoned its fishing nets to get away from the Coast Guard.

The Jarvis had received a radioed tip that the Tyi Yang, which was supposed to be fishing for squid, had drift nets in the water fishing illegally for salmon. Salmon is a far more lucrative catch than squid.

Such fishing on the high seas runs counter to Taiwanese law and has been the subject of a bitter dispute between the United States and North Pacific fishing countries, including Taiwan, that have been suspected of poaching North American salmon.

U.S. authority over vessels from other countries is limited to America's 200-mile zone. The Jarvis came upon the Taiwanese vessel outside the U.S. fishing zone, so the State Department had to obtain permission for a Coast Guard boarding.