Colombo - The military said Saturday that it had killed at least 26 Tamil rebels and lost six soldiers in northern Sri Lanka as it fights to capture the last remaining guerilla-held ground on the island.

Military spokesman Brigadier Udaya Nanayakkara said the fighting occurred around Pudukudirrippu and Karaivamulliyakal, 390 kilometres north-east of Colombo.

Government troops reached the outer perimeters of a "no-fire zone" meant for civilians in the north-eastern part of the country, which is in the rebel-held area, he said.

It was not immediately clear how troops would react if rebels with the Liberation Tigers of Tamil Eelam (LTTE) shoot from inside the zone unilaterally declared by the government for civilians.

The government estimated that about 50,000 civilians still remain in the area and claimed the LTTE is preventing them from leaving.

Since January, about 59,000 civilians have fled the conflict zones or been evacuated.

The LTTE 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)