The stranded tourists, mostly foreigners, were being evacuated to the popular destination of Ko Samui, a larger island south of Koh Tao, the navy's chief of staff Admiral Satirapan Keyanon said.

"Three navy ships are now transporting an estimated 300 tourists to Ko Samui," Satirapan told AFP.

Ferry services to Koh Tao have been cancelled for nearly a week due to the severe weather and flights to Samui were also suspended temporarily Thursday.

The poor conditions were hampering a rescue operation for 18 fishermen missing since Wednesday when the fierce tropical storm hit the Gulf of Thailand.

But Satirapan said the navy had managed to pull ashore one more fishing trawler and its crew of seven late Thursday.

Five naval vessels and some 100 navy and marine police officers were still taking part in the rescue operation, braving mountainous seas and driving rain to search for those still unaccounted for.

"We cannot find some 18 fishermen still missing. Although we have support from helicopters, due to the poor visibility they cannot fly and the rescue operation cannot be fully implemented," he said.

WAR.WIRE