According to the Red Cross, some 250,000 noncombatants are stuck in the 115-square mile (300-square kilometer) area near the northern town of Mullaittivu where advancing government troops have boxed in the separatist Tamil rebels. The government puts the number at about 120,000.

``The humanitarian situation is precarious if not critical,'' Red Cross spokeswoman Sarasi Wijeratne told The Associated Press. ``We have appealed to both parties to allow safe passage for the sick and wounded so that they can get medical treatment,'' she said.

There are no accurate figures for the casualties in the recent fighting. The government denies independent reports that more than 300 civilians have been killed.

President Mahinda Rajapaksa's government, which accuses the Tamil Tigers of keeping civilians in the war zone to use as human shields, had given the insurgents Friday and Saturday to let the noncombatants leave the area.

By the time the deadline expired, only 236 civilians had emerged from the battleground to cross the front line into the government-held areas, according to the Media Center for National Security.

The Tigers deny holding civilians and claim the military offensive is preventing them from fleeing.

Wijeratne said the Red Cross knows of only one functioning hospital in the area, and it is overwhelmed by some 500 patients, many of them in serious condition waiting to be evacuated.

``There hasn't been any medical evacuation since Thursday'' when 226 people were taken out, she said.

On Saturday, ground troops fought their way into the jungles to uncover two camps of the Black Tigers, the rebels' suicide bombing squad, north of Mullaittivu, said an official of the media center who cannot be identified under briefing rules.

He said one camp comprised a two-story underground apartment with luxurious bedrooms, bathroom, an electricity generator and a refrigerator. In the other camp, the troops found a large number of weapons including mortar launchers, rifles, rocket propelled grenades, light machine guns, grenades, mines, bombs, detonators, gas masks and Tamil Tiger uniforms.

The bodies of 12 rebels were also recovered, apparently killed by the troops in the fighting, said military spokesman Brig. Udaya Nanayakkara.

``It is a big success because that means the Tigers are leaving their camps and fleeing,'' he told the AP.

The claim could not be independently verified because journalists have been barred by the government from going into the conflict zone. The rebels also did not immediately issue any statement on the current battle situation.

The military believes it is now close to destroying the Tigers, who have been fighting since 1983 for a separate homeland for ethnic minority Tamils in the north and the east.

More than 70,000 people have been killed in the 25-year civil war, which grew out of complaints by Tamils, who have suffered decades of marginalization under successive governments controlled by the Sinhalese majority.

Also Sunday, Defense Secretary Gotabhaya Rajapaksa warned Western diplomats, foreign journalists and aid groups that they would be ``chased'' out of the country if they appear to favor the rebels.

In the northern town of Jaffna, which was once a Tiger stronghold, thousands of pro-government Tamils marched through the streets to demand that the rebels let the civilians leave the war zone.

``These innocent people want to come out. They should be allowed to come out from the war zones,'' said a demonstrator, Murugpillai Sripathi, 62.

Associated Press reporter Jay Palipane in Jaffna contributed to this story. Published: Sun Feb 1 08:00:22 EST 2009