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. 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.