COLOMBO, Nov 20: Sri Lanka's military said on Thursday it smashed a key Tamil Tiger defence line in the island's far north and seized an airfield, putting new pressure on the shrinking jungle mini-state.

Government troops took a near five-kilometre fortified bunker line from the Liberation Tigers of Tamil Eelam (LTTE) on the Jaffna peninsula after five days of fierce fighting, the defence ministry said.

It said troops had also captured an air strip that had been used by the guerrillas for clandestine air sorties using light aircraft.

Officials said the air strip was located near Paranthan, in the northern edge of the mainland but there was no sign of the Zlin-143 planes operated by the rebels.

The reported capture of the air strip came hours after troops further north claimed they had broken through a key Tiger fortified bunker line.

“In a continuous military thrust launched by the 53 and 55 Divisions, terrorists were unable to defend their defence line,” the statement said, adding Tigers suffered “scores” of losses while troops “minimised” their casualties.

The Tigers are known to maintain fallback positions, but the collapse of the defences adds to the pressure they have been facing on other fronts, including around their political capital of Kilinochchi and coastal base of Mullaitivu.

“The army shifted its mode of operations from active defence to an all-out offence in the northern theatre on Saturday by running at the LTTE's forward defence lines” on the Jaffna peninsula, the defence ministry said.

Jaffna is controlled by the government, but cut off from the rest of government-held territory by the Tigers who are battling to carve out a separate state in the north and east of the ethnic Sinhalese-majority island.

Sri Lankan authorities, who pulled out of a Norwegian-brokered truce with the rebels at the start of the year, have been on the march from the south for several months.

The defence ministry said troops from Jaffna were now “heading further southwards.” Sri Lankan authorities have restricted access to the embattled areas for journalists as well as for most aid workers, meaning that claims by either side in the decades-old conflict are normally impossible to independently verify.

There was no immediate comment from the Tigers on the latest military statement.

Reports on the humanitarian situation in the north, meanwhile, were dire.

Human rights watchdog Amnesty International said Sri Lanka was unable to provide for the basic needs of 300,000 people trapped inside rebel-held areas of the island's north and accused Tiger guerrillas of using them as human shields.

The rights watchdog said two-thirds of people living in the rebel-controlled northern area of Wanni have been driven out of their homes in the ongoing wave of fighting. “More than 300,000 people face the next few months crowded together in temporary shelters, surrounded by mud, with no promise of regular access to food or adequate sanitation,” Amnesty's Asia Pacific Director Sam Zarifi said.

Sri Lanka insists it is able to look after its internally displaced citizens and accuses Amnesty International of making charges based on incorrect information.

—AFP