Sri Lanka's Tamil Tigers said on Sunday peace talks were impossible as the worst fighting since a 2002 truce raged in the island's north and the government demanded rebel fighters surrender.
The government had said it received a message from the Tigers through cease-fire monitors on Friday, hours before clashes erupted on the northern Jaffna peninsula, saying that they were keen to talk - something the government said it was keen to do.
"We have made no proposals for peace talks," S. Puleedevan, head of the Tiger peace secretariat, told Reuters by telephone from the northern rebel stronghold of Kilinochchi. "Government offensive attacks make peace talks impossible."
The government says it is winning the fighting, although analysts are sceptical. A statement late on Sunday said many Liberation Tigers of Tamil Eelam (LTTE) fighters were deserting and called on them to put down their weapons and surrender to the security forces.
"Security forces confirm there are many child recruits amongst the LTTE cadres killed in the confrontations that took place in the last 48 hours," the statement said. "The government requests all child recruits and other LTTE cadres to surrender to the nearest security forces camp or police station."
On Saturday the LTTE broke through army defences on the Jaffna peninsula, where some 40,000 troops, mainly from the Sinhalese majority, are based in a Tamil-dominated area cut off from the rest of the island by rebel territory.
Telephone lines to Jaffna appear completely out of action, but aid agencies report heavy shelling. Most aid staff are sheltering in well-marked compounds, although there were no reports of shells hitting Jaffna town.
"The confrontation is continuing," said an army spokesman."
Truce monitors said fighting seemed slightly less than on Saturday. The army says 30 soldiers have been killed and 110 wounded in the Jaffna battle.
Monitors said they believed the LTTE were trying to cut supply lines to Jaffna, which has changed hands several times in two decades of civil war that has killed more than 65,000 people.
The birthplace of most of the rebel leadership and cultural centre of their fight for a homeland for minority Tamils, Jaffna has long been seen as a key Tiger objective. Some diplomats believe the LTTE wants to move closer before going to peace talks.
Aid workers said people inside rebel territory were fleeing south towards Kilinochchi, some of them sheltering at the roadside as spotter planes flew overhead.
The first ground fighting since the cease-fire erupted over a week ago further south, initially sparked by the closure of a rebel-held sluice gate providing water to government territory. The Tigers later opened the sluice gates but violence continued.
The fighting has been accompanied by targeted attacks in the island's south, far from the front. On Saturday, gunmen shot dead the deputy head of the government peace secretariat Kethesh Loganathan, an ethnic Tamil.
The government blames the rebels, who have long silenced dissenting Tamil voices. Loganathan supported the government's military campaign against the rebels and last week told Reuters the international community was "mollycoddling" the LTTE.
The army said two men took cyanide after they were arrested outside a police station in the capital Colombo on Sunday near a vehicle packed with explosives. One died. Tiger fighters often try to commit suicide rather than face capture.