An exodus of civilians fleeing the fighting in northern Sri Lanka has picked up, with more than 1,500 escaping in the last day, the government said Wednesday.

Tens of thousands of terrified civilians are trapped in a sliver of jungle and beach along the island's northeast coast where government troops are battling to dislodge remnants of the Tamil Tiger separatist rebels.

A statement on the government's Web site said 1,515 people, including nearly 650 children, had crossed into military-controlled areas by late Tuesday near Puthkkudiyirippu, the last rebel-held town, where battles have been raging for weeks.

The statement said the civilians were being screened and would be taken to displacement camps in the island's interior.

The military also said its troops captured a safe house belonging Pottu Amman, the rebels' powerful intelligence chief.

Independent accounts of the fighting are not possible because access to the war zone is restricted.

There has been a surge in civilians fleeing the area amid an all-out army offensive that the government hopes will soon end the civil war.

Risks to the civilians have led the United Nations, European Union and numerous countries to voice concern. The U.N. has said 2,800 civilians caught in the fighting have been killed since late January, though the government disputes that figure.

The U.N. estimates at least 150,000 civilians are trapped in the war zone. The government says the number is closer to 50,000 to 60,000, and accuses the rebels of using them as human shields in a bid to avoid defeat.

A separate notice on the military's Web site Wednesday said the rebels fired surface-to-air-missiles at two air force helicopters evacuating military casualties. It said the rockets, which forced the pilots to take evasive action, were fired from the "no-fire" zone set up to shelter the civilians.

The military also said Wednesday that suspected Tamil rebels shot dead five farmers and wounded two others in a village in the east. No reason was given for the attack. The rebels often punish civilians who do not support them or resist being recruited into their ranks.

The rebels could not be reached for comment since communication with their stronghold has been severed.

The rebels have been fighting since 1983 for an independent state for the Tamil minority, which suffered decades of marginalization at the hands of governments dominated by the Sinhalese majority. More than 70,000 people have been killed in the fighting.