Colombo- Government troops Thursday thrust further into the last areas held by Tamil rebels on Sri Lanka's north-eastern coast, military officials said, as the United Nations Security Council called on the rebels to surrender.

More than 2,000 civilians escaped from the Puthmathalan area, 390 kilometres north-east of the capital Colombo, Thursday morning, putting the total number of civilians who fled the area since Monday to 102,790.

The army cornered the Liberation Tigers of Tamil Eelam (LTTE) Tamil rebels in an area of less than 8 square kilometres and the remaining civilians were confined mostly to the beach, military officials said.

The LTTE rebels were still putting up resistance, trying to prevent the army from overrunning their last positions where the rebel leaders are believed to be hiding.

The military believes rebel leader Velupillai Prabhakaran is still in the area, though there was speculation that he had already managed to escape.

So far only two prominent LTTE members have surrendered to the security forces. Former LTTE media co-ordinator Valaiutham Dayanidhi, alias Daya Master, and Anthonipillai George, a translator for former LTTE political wing leader SP Thamilselvan who was killed in an air raid in November 2007, gave themselves up Wednesday.

On Monday the government offered a 24-hour period for the rebels to surrender, but there was no official response.

The United Nations Security Council, after an informal meeting late Wednesday in New York, expressed its concern with the plight of civilians.

In a non-binding statement it urged the Tigers to surrender, and called on the Sri Lankan government to protect civilians and allow international agencies access to victims of the conflict.

It urged the LTTE to stop using civilians as human shields and join peace talks.

"The Security Council members, we expressed our deep concern about the humanitarian situation ... and the plight of the civilians trapped within the conflict area," said Mexican UN ambassador Claude Heller, who chaired the meeting.

"We strongly condemn the terrorist organization for the use of civilians as human shields," he added.

Meanwhile, a food ship operating under the Red Cross flag which was heading to the north to send food supplies to civilians in the rebel-held areas was not able to reach the coast due to the fighting.

Before Monday, an estimated 68,000 civilians had left the rebel areas and are currently in camps controlled by the government.

The military says it is in the final phase of a military drive to crush the LTTE, which has been fighting for more than 25 years for a separate state for the Tamil ethnic minority in the northern and eastern parts of majority-Sinhalese Sri Lanka. (dpa)