COLOMBO - The Sri Lankan army foiled a last-ditch, pre-dawn attempt by the Tamil Tigers to breach military defences Sunday, killing at least 70 fighters and destroying six vessels, a military spokesman said.

Brigadier Udaya Nanayakkara said the rebels, initially posing as civilians, had come across a lagoon and made an attempt to breach the defences around 1.30 a.m., but were confronted and killed.

He did not say whether the army suffered any casualties in the incident.

The defence ministry also announced that almost all civilians from the recaptured rebel zones had been rescued, as search efforts were continuing to find any sick or disabled people left behind.

As many as 36,000 civilians were rescued in 24 hours through Sunday morning, far exceeding official estimates about the number of civilians in the area. Since Thursday, more than 50,000 civilians have been rescued, while the government had previous insisted that only about 20,000 civilians were trapped in the combat zone.

The ministry made no mention about the current state of fighting, though other military sources said there were reports continuing operations against in the area.

The sweep operations came as the country awaited a formal announcement on the end of the 25-year war against the Liberation Tigers of Tamil Eelam (LTTE).

Sri Lankan President Mahinda Rajapaksa received a warm welcome on his return to the country from Jordan Sunday as crowds outside the Bandaranaike International Airport waved national flags and cheered.

Rajapaksa declared Saturday from abroad that the Tamil rebels had been finally defeated militarily, but on arrival he made no public statement.

The president was due to make a formal announcement in a nationwide address. Government sources said his address was likely to come after Rajapaksa briefs his cabinet ministers later in the day.

The military earlier reported a series of loud explosions in the last rebel enclaves, but have not given details of the damages caused.

Army sources had claimed that senior rebel leaders, including their chief Velupillai Prabhakaran, were trapped in the combat zone, but the government has not confirmed the fate of those leaders.

An estimated 250,000 civilians have fled the rebel zones since January and are now in refugee camps in the northern province.

Troops launched their offensive in August 2006 to recapture rebel held areas in north and eastern parts of Sri Lanka and gradually cornered them into a narrow land strip on the northern coast.

The fighting in the coastal area was the most difficult part of the operation, as the troops had to move in an area where thousands of civilians were trapped, with the rebels preventing some of the civilians from leaving.