Military spokesman Brig. Udaya Nanayakkara in Colombo. (AP)

Colombo, Oct. 15 (AP): Government forces pounded rebel defences with airstrikes and ground assaults as heavy fighting across northern Sri Lanka killed 49 Tamil Tiger fighters and seven soldiers, the military said today.

The new fighting came as soldiers closed in on the rebels’ administrative capital of Kilinochchi in a campaign aimed at routing the guerrillas and ending a 25-year-old war that has killed more than 70,000 people.

Out of the newly reported battles, the worst took place yesterday in Kilinochchi where 39 rebels and six soldiers died, military spokesman Brig. Udaya Nanayakkara said. The army has said its forces are about 1.6km from the outskirts of Kilinochchi.

Scattered battles in Vavuniya, Mannar and Mullaitivu killed 10 rebels and a soldier yesterday, Nanayakkara said.

Today, air force jets bombed a group of rebels who were building an earthen embankment as a defence against advancing government forces in Mullaitivu, said air force spokesman Wing Commander Janaka Nanayakkara.

He said the attacks were successful, but details of damage and casualties were not immediately available.

With nearly all communications to the north severed, a rebel spokesman could not be contacted for comment. Independent verification of the military's claims is nearly impossible because most journalists are banned from the war zone. Both sides routinely exaggerate enemy losses and underreport their own.

During the afternoon, Lankan troops were involved in three separate confrontations in the Vannerikkulam area. They reported killing three Tiger rebels while six soldiers were injured.

The troops are advancing into Kilinochchi in several formations and are reported to be just 2 to 3km from the town.

Lankan troops also hit LTTE dominated areas in Madamoddai yesterday, the defence ministry said, adding that 10 Tiger cadres were killed and many others injured.

Fighting has escalated in recent months, with the military capturing a series of rebel bases and large chunks of territory. Officials have pledged to crush the guerrillas by the end of the year.

The rebels have been fighting since 1983 to create an independent homeland for Tamils, who have faced marginalisation by successive governments controlled by ethnic Sinhalese.