COLOMBO (Sri Lanka) - SRI Lanka firmly rejected a European Union appeal for an immediate cease-fire in the island's civil war on Tuesday, saying any deal would allow the besieged Tamil Tiger rebels to regroup.

Meanwhile, fighting raged around the last rebel enclave in the island's war-ravaged north on Monday, leaving at least 36 guerrillas dead, according to the military.

The EU urged the government and Liberation Tigers of Tamil Eelam to allow urgent humanitarian aid into a northern 'safe zone' where a largely Tamil civilian population is supposed to be shielded from the fighting.

'What are we going to achieve with a cease-fire other than giving in to the demands of the LTTE?' said Foreign Secretary Palitha Kohona.

Mr Kohona accused the rebels of using civilians as human shields in a desperate bid to avoid defeat as the military closes in on victory in the 25-year civil war, and said they should immediately release them.

'They are holding their own people hostage, the international community should recognize this,' he said.

Mr Kohona said the rebels - who are struggling to hold onto a shrinking swath of land estimated at 35 square kilometres on the north-east coast - would use any interruption in the fighting to acquire weapons and regroup.

In making the appeal for a cease-fire, Benita Ferrero-Waldner, the EU's external relations commissioner said Monday the situation for the trapped civilians is 'very dangerous.' 'Approximately 170,000 people ... are being trapped in the northern part of Sri Lanka and neither the Sri Lanka government or the LTTE has until now accepted our appeal,' she told reporters.

She said the EU would send a diplomatic mission to the country soon to push the EU cease-fire appeal.

UN estimates of the number of civilians trapped in the rebel area are similar to the EU's, but the government says the figure is much lower. The United Nations also estimates some 2,800 civilians have died since late January; the government says that figure is unsubstantiated. -- AP