Some 600 soldiers tried to enter rebel territory in Mullikulam village some 180 kilometers (111 miles) north of the capital, Colombo, rebel spokesman Rasiah Ilanthirayan said by telephone from the guerrillas' headquarters in the northern town of Kilinochchi.

Rebels fired back and the soldiers ``retreated with the casualties,'' Ilanthirayan said without giving details.

Military spokesman Brig. Prasad Samarasinghe said that there was no such clash reported by troops from the region.

Last week, eight people including four military men and four wildlife department employees were found killed inside a sanctuary south of Mullikulam. The military blamed the Tamil Tigers for the killings but the rebels refused to comment on the incident.

Tamil Tiger rebels have fought the government since 1983 to create an independent state for the country's ethnic minority Tamils following decades of discrimination by the majority Sinhalese-dominated state.

A Norway-brokered cease-fire signed in 2002 resulted in relative peace but a resurgence of violence since late 2005 has killed 4,000 people, according to European monitors, rendering the cease-fire valid only on paper.

More than 65,000 people died before the cease-fire was signed.Discuss this story Published: Thu Mar 15 12:38:50 EDT 2007

Details about casualties and damage from the airstrikes on the Thoppigala camp were not immediately known.

The camp has been a major Tiger training center and is considered one of the rebels' last eastern strongholds after Sri Lankan forces captured swaths of rebel territory in ground and air attacks over the past year.

A rebel spokesman confirmed the air raid, but said the insurgents suffered no casualties. However, resurgent fighting in recent weeks has triggered a sharp rise in refugees seeking safety, especially in the eastern district of Batticaloa.

``The influx of tens of thousands of civilians has increased the total number of internally displaced persons (IDPs) in conflict-affected Batticaloa district ... to over 130,000,'' the U.N. statement said, pleading for immediate funding to help the refugees.

``The United Nations has almost no funds to meet even the most basic requirements of the IDPs,'' it said. ``The most urgent need at the moment is food, with the World Food Program reporting that they do not have the additional in-country stocks for this latest influx.''

``Other priority areas include shelter and water and sanitation, areas that were already under severe strain,'' it said.

The Sri Lanka - Common Humanitarian Action Plan for 2007, which called for US$66.2 million (euro50.22 million), has so far received only $2.7 million (euro2.05 million), or 4 percent of the funding required, according to the United Nations' Office for the Coordination of Humanitarian Affairs.

The Tamil Tigers have been fighting since 1983 to create a separate state for Sri Lanka - 's minority ethnic Tamils in the island country's north and northeast, following decades of discrimination by the Sinhalese majority.

About 65,000 people died in the conflict before a Norwegian-brokered cease-fire was signed in 2002.

But the truce faltered in late 2005. Renewed fighting has since killed about 4,000 people, European cease-fire monitors say.Discuss this story Published: Thu Mar 15 07:26:30 EDT 2007