On Friday, the army was trying to take the rebel-held town of Sampur, from where the rebels were in artillery range of a major naval base and able to disrupt a key maritime supply route to the besieged army-held northern Jaffna peninsula.
A military spokesman said: "We are trying to neutralise the threat to Trincomalee.
"Our strategy is to send people into Sampur to neutralise their artillery and mortar positions which are pointed towards the harbour."
He said 14 soldiers had been killed and 92 wounded since the offensive began on Sunday. The army estimates around 120 rebels were killed. The Tigers were not immediately reachable.
Officials said more than 20 lorries carrying government aid had been allowed into rebel territory through a "border" crossing in the northern district of Vavuniya since Thursday.
The Essential Services Commission was loading 3,600 tonnes of emergency aid and food purchased by shop owners to sail to the northern Jaffna peninsula, which is cut off from the rest of the island by rebel lines and where shop shelves are empty. It was expected to sail on Sunday.
Residents in Jaffna said the peninsula had been quiet for the past 24 hours after fierce artillery exchanges between the rebels and the military.
The main opposition party has agreed to help find ways to halt the renewed civil war.
Ranil Wickremesinghe, the opposition leader, wrote to the president, Mahinda Rajapakse, saying he was ready to discuss ways "to resolve the national issue", party officials said. Previous collaborations have come to nothing, and the Tigers trust neither side.
"We are trying to neutralise the threat to Trincomalee.”
A military spokesman
Rajapakse met the British prime minister, Tony Blair, in London on Thursday to discuss lessons learnt from Northern Ireland's peace process.
Palitha Kohona, Sri Lanka's government peace secretariat head, told Reuters by telephone from London late on Thursday: "Both sides expressed the hope the two parties would be back to the negotiating table sooner than later.
"Britain has extensive experience in dealing with a (conflict) situation of this nature."
A 2002 ceasefire between the government and Tigers is technically still in force, but survives only on paper.
The Tigers say they are fighting for a separate homeland for ethnic Tamils in the north and east.
Analysts expect fighting to rumble on. They say any idea of a return to the negotiating table to end a conflict that has killed more than 65,000 people since 1983 is a dim and distant prospect.