COLOMBO: Sri Lanka's president rejected international appeals for cease-fire in his nation's bloody civil war Thursday, as the Tamil Tiger rebels vowed never to surrender to the advancing government forces.

The defiant declarations came in the face of growing calls for Sri Lanka to halt its offensive against the rebels' last stronghold in the northeast to allow an estimated 50,000 civilians to flee the war zone.

"The government is not ready to enter into any kind of cease fire with the terrorists," President Mahinda Rajapaksa said in his first public comments since the British and French foreign ministers asked him to accept a humanitarian truce.

Rajapaksa said his government was trying to rescue the trapped civilians, and appeared impatient at the continued demands for him to call off his forces.

"It is my duty to protect the people of this country. I don't need lectures from Western representatives," he said, according to highlights of a speech he delivered in the southeastern town of Embilipitiya that were distributed by his office.

Defense Secretary Gotabhaya Rajapaksa, the president's brother, said the war would not end until rebel leader Velupillai Prabhakaran is captured or killed, according to The Island newspaper.

The rebels, meanwhile, called on the international community to work harder to stop the war — while also saying they wouldn't give up their fight.

"If any country really cares about these people, I ask that country to go beyond its 'diplomatic boundaries' for the sake of saving human lives and make Sri Lanka stop this genocidal war," rebel political chief Balasingam Nadesan told The Associated Press in an e-mail interview from the war zone.

In recent months, government troops have forced the Tamil Tigers out of the shadow state they controlled in the north of the country and cornered them in a tiny sliver of land along the northeast coast. The U.N. says nearly 6,500 ethnic Tamil civilians have been killed in the offensive.

The rebels called for a cease-fire Sunday; the government demanded the separatists surrender instead. Nadesan rejected that demand.

"Surrendering and laying down our arms are out of the question. Our freedom struggle will continue until (our) legitimate aspirations are met," he said.

French Foreign Minister Bernard Kouchner and his British counterpart, David Miliband, came here Wednesday to express the EU's concern over the rising civilian death toll.

Japan announced that its special mediator for the conflict, Yasushi Akashi, would arrive here Thursday to further press the government to protect the civilians.

The government and international rights groups have accused the rebels of holding the civilians still in the war zone as human shields to slow the government offensive.

Nadesan dismissed the accusation as government propaganda.

"We all are family. How could anyone hold his or her family as a 'human shield?'" he asked.

He also denied reports that the rebels' top leaders had fled the country, saying they "are still in our homeland and leading the freedom struggle."

The Tamil Tigers have been fighting since 1983 for a state for minority Tamils in the north and east after decades of marginalization by governments dominated by the Sinhalese majority.

The government said Monday it would cease using heavy weapons in the 3-mile- (5-kilometer-) long strip still controlled by the rebels because of the dense concentration of civilians there. However, reports from health officials in the area said airstrikes and shelling have persisted.