Dr Thoufeek, chairman of the government in the eastern coastal town of Mutur, said 700 to 800 families around 10 percent of the population left on Friday and Saturday after the Tamil Tiger separatists warned of an impending offensive.

Mutur's residents, who are mostly Muslims, only returned to their homes two weeks ago from refugee camps. They had been driven from the town by weeks of heavy fighting and artillery assaults in August that killed dozens of civilians.

Foreign mediators are struggling to keep alive a 2002 cease-fire amid clashes that have killed at least 1,000 combatants and more than 100 civilians since July.

On Friday, hundreds of people boarded boats in Mutur, about 140 miles east of the capital, Colombo, and sailed for the nearby Muslim-majority island of Kinniyai, Thoufeek said in a telephone interview.

Government forces refused to let them pass by road, he said.

Witnesses said the roadblocks were removed Saturday after meetings between the government and local authorities. Some 8,000 Muslim families live in the area.

Many had reluctantly returned home in time for the Islamic holy month of Ramadan, which begins Sunday in Sri Lanka, but will now leave "because of another disaster," Thoufeek said.

The Tamil rebels began fighting in 1983 for a separate homeland in the north and east for Sri Lanka's largest ethnic minority.

The conflict was nominally halted by a Norway-brokered cease-fire in 2002 although the recent wave of violence has threatened to drag the country back into full-scale civil war.

Norwegian Ambassador Hans Brattskar on Friday met the Tamil Tigers' political leader, Suppiah Thamilselvan, in the northern rebel stronghold. The two discussed a recent rash of abductions, the rebels said on their official Web site. No additional details were available.