The Sri Lankan army launched a new offensive against the Tigers last week after three months of stalemate.

The operation, codenamed Ranagosa, or Battle Cry, is not reported to have met any resistance from the Tigers.

"Operation Ranagosa was launched with the objective of expanding the security forces-controlled area in Wanni," the defence ministry said in a statement.

"Troops had no confrontation as they managed to maintain surprise, and the terrorists fled the area with the arrival of the troops."

Rebels withdraw

The defence ministry said its soldiers had taken more than 500 square kilometres of land, including 24 villages. The captured area covers a long strip to the west of the main road dividing the Tiger-held area in two.

The government has ordered food and medical supplies to be distributed to civilians in the newly captured areas.

The BBC Colombo Correspondent, Susannah Price, says the rebels appear to have withdrawn their fighters in the face of the government advance. There are no reports of casualties, as it appears the Tigers withdrew all personnel, including their own police, before the soldiers arrived.

Our correspondent says the offensive comes ahead of provincial elections and could provide a badly-needed boost to the government's popularity.

No comment from Tigers

The Tigers have been fighting government forces for a separate state for minority Tamils in Sri Lanka's north and east since 1983. They say the majority Sinhalese - who control the government and military - discriminate against them.

Although the Tamil Tiger radio station has quoted newspaper reports about the offensive, it has made no comment of its own.

There has been no independent confirmation of the government's account of the clashes.

It is the first government offensive since a limited operation codenamed Rivibala in early December, in which troops captured a triangular area of land, again without meeting resistance.