At least 800 civilians caught in raging fighting escaped Sri Lanka's war zone yesterday, the military said, and the government renewed a call for Tamil Tiger rebels to surrender unconditionally or face destruction.

Battles flared around a shrinking wedge of jungle in the Indian Ocean island's northeast, that the military now measures at about 200 sq km and in which the Liberation Tigers of Tamil Eelam (LTTE) are trapped.

Tens of thousands of civilians are also being held there by the Tigers, under grave threat of harm from the fighting and a lack of food and medicines, aid agencies say.