COLOMBO: Sri Lanka's president declared victory Saturday in his nation's quarter century civil war with the Tamil Tigers rebels. But the group's top leaders remained at large as troops and the cornered insurgents fought fierce battles across the war zone.

A triumph on the battlefield appeared inevitable after government forces captured the last bit of coastline under rebel control early Saturday, surrounding the remaining fighters in a 1.2-square mile (3.1-square kilometer) patch of land.

Thousands of civilians who had been trapped by the fighting poured across the front lines, the military said.

"My government, with the total commitment of our armed forces, has in an unprecedented humanitarian operation finally defeated the LTTE militarily," President Mahinda Rajapaksa said referring to the rebels by their formal name, the Liberation Tigers of Tamil Eelam.

"I will be going back to a country that has been totally freed from the barbaric acts of the LTTE," he said in a speech in Jordan that was distributed to the media in Sri Lanka.

The rebels, who once controlled a de facto state across much of the north, have been fighting since 1983 for a separate state for minority Tamils after decades of marginalization by the Sinhalese majority. Responsible for hundreds of suicide attacks — including the 1991 assassination of former Indian Prime Minister Rajiv Gandhi — the Tamil Tigers have been branded terrorists by the U.S., E.U. and India and shunned internationally.

The rebels also controlled a conventional army, with artillery units, a significant navy and even a tiny air force.

After repeated stalemates on the battlefield, the military broke through the rebel lines last year and forced the insurgents into a broad retreat, capturing their administrative capital at Kilinochchi in January and vowing to retake control over the rest of the country.

The rebels have insisted that if they are defeated in conventional battle, they will return to their guerrilla roots.

On Saturday morning, government troops sweeping in from the north and south seized control of the island's entire coastline for the first time in decades, sealing the rebels in a tiny pocket of territory and cutting off the possibility of a sea escape by the rebels' top leaders, the military said.

Government forces have been hunting for the reclusive rebel leader Velupillai Prabhakaran and his top deputies for months, but it was unclear if they remained in rebel territory or had already fled overseas.

Two senior fighters, known by their nicknames Sornam and Sasi Master, were killed in Saturday's fighting, Nanayakkara said. On Friday, the navy intercepted a boat off the northeastern coast Friday and arrested the fleeing wife, son and daughter of the rebels' naval leader, known as Soosai, Nanayakkara said.

Even as Rajapaksa declared victory, the military reported that fighting continued to rage in the northeast war zone. Huge explosions could be heard across the battlefield as rebels detonated their ammunition stocks and artillery dumps, military spokesman Brig. Udaya Nanayakkara said.

Reports of the fighting are difficult to verify because the government has barred most journalists and aid workers from the conflict zone.

Some 11,800 civilians escaped the war zone Saturday, joining more than 200,000 others who fled in recent months and are being held in displacement camps, Nanayakkara said. Rights groups say the rebels were holding the civilians as human shields to blunt the government offensive. The rebels denied the accusation.

U.N. spokesman Gordon Weiss said an estimated 20,000 people had emerged from the combat zone in the past few days and were being processed by the government.

"We have no access to that process. We hold grave fears for the safety of the estimated 30,000 to 80,000 people who are still inside the combat zone," he said.

Weiss expressed concern for the fate of the top government health officials working in the war zone — Dr. Thurairaja Varatharajah and Dr. Thangamuttu Sathyamurthi — "who courageously kept the medical services going throughout the months of the siege of the combat zone."

The pair ran a badly understaffed makeshift hospital in the war zone that was repeatedly shelled and overwhelmed with hundreds of casualties from the fighting nearly every day.

The U.N. says 7,000 civilians were killed and 16,700 wounded from Jan. 20 through May 7. Since then, health officials say more than 1,000 civilians have been killed in a week of heavy shelling that rights groups and foreign governments have blamed on Sri Lankan forces.

The government denied firing heavy weapons and brushed off calls for a humanitarian truce.