Sri Lanka's Tamil Tigers warned the army on Monday they would resort to pre-emptive strikes if the military pushes ahead with a declared plan to drive them out of rebel-held territory in the island's volatile east.
The military says more than 17,000 war-displaced have fled camps in and around the Tiger-held town of Vakarai in the district of Batticaloa, some through jungle and others by sea, since early November to escape artillery duels.
The army accuses the Tigers of using civilians as human shields and, to the shock of Nordic truce monitors, has vowed to push them out of areas they control under the terms of a tattered 2002 ceasefire pact, which still holds on paper.
The rebels say the civilians are fleeing because of army artillery shells that have hit refugee camps and killed dozens.
They deny they have held civilians against their will as some witnesses have said.
"The flushing-out plan ... is not about flushing out the LTTE, it's about displacing all Tamils," Tiger military spokesman Rasaiah Ilanthiraiyan told the agency by telephone from the rebels' northern stronghold.
"It has been happening since independence."
"We will resist in every way. The Sri Lankan government is already in a full-fledged war.
It takes two to tango," he added. "If they accumulate more forces to launch against us, then we will have to make pre-emptive actions in future."
Asked if that would include attacks on the capital, given a spate of suicide attacks and killings in recent months, he said the pre-emptive strikes would be confined to the battlefield.
The military has hemmed the Tigers in to a 14-mile stretch of coastline around Vakarai, and has already driven the rebels out of territory near the strategic northeastern port of Trincomalee further north.
"There is a threat to the civilians in Trincomalee south. They are firing artillery and mortars," said military spokesman Brigadier Prasad Samarasinghe.
"So as a defensive measure, we have to get these LTTE mortars and artillery neutralised for these civilians to be resettled."
Thousands of displaced are now crammed in to temples, schools and welfare camps in government terrain, many with little more than the clothes on their backs and living on food handouts.
The United Nations, the Red Cross and the international community have all called on both sides to halt the fighting and guarantee the safety of civilians trapped in the crossfire, but both sides have ignored them.
More than 3,000 troops, civilians and rebel fighters have been killed so far this year in a series of land battles, air strikes, ambushes and attacks.
The conflict has killed more than 67,000 people since 1983.
The Tigers, who accuse successive Sinhalese-majority governments in Colombo of discriminating against minority Tamils, say they are intensifying their fight for an independent state in the north and east after President Mahinda Rajapaksa rejected their demands for a separate homeland.