Soldiers, backed by armour, artillery and air cover, thrust to within six miles of Kilinochchi in a fresh offensive that followed some of the worst fighting in Sri Lanka's long ethnic war.
It began two days after bombs blamed on Tamil Tiger separatists killed 78 people and wounded 450 on a commuter train at a suburban station in Colombo.
The Tamil Tigers, fighting for an independent homeland in the north and east in a war the government says has cost more than 50,000 lives, denied responsibility for the latest in a series of bombings to hit the Sri Lankan capital.
But police have focused their search for the culprits on the Tamils. Yesterday, police said they were holding some 2,000 people in the northern town of Vavuniya as they headed to the largely Tamil north from the predominantly Sinhala south.
The Tamil Tigers, who were thought to have been severely weakened by the government's recapture of their Jaffna peninsula stronghold earlier this year, recently claimed a major victory following a devastating attack on a north-eastern army base.
Both sides claim they control the Mullaitivu base, but agree hundreds of fighters were killed in fighting that began with a surprise rebel attack last week.
The military admitted the base was overrun, but said it was retaken in a counter-attack by troops sent in by sea and air.
It said soldiers under rebel mortar fire were moving carefully into the base, wary of any booby-traps the Tigers might have left.
In the new offensive, a military communique said forces pushing south from their Elephant Pass base at the neck of the Jaffna peninsula towards Kilinochchi had met some resistance, but their superior firepower had overcome it.
The army said it had declared an indefinite curfew in Kilinochchi and had told civilians to take shelter in religious places and schools. It was not immediately clear how the army had transmitted its message or what effect it would have. The Tamil Tigers said army shells had hit civilians in Kilinochchi, which houses the region's main medical facilities.Reuse content