The Sri Lankan government has rejected a US-led call to negotiate with the Tamil Tigers, vowing instead to crush the cornered rebels by force despite mounting evidence of civilian casualties.
Defence Secretary Gotabhaya Rajapakse said he would only accept the complete surrender of the Tigers who are facing imminent defeat in their decades-long fight for an independent ethnic Tamil homeland.
Concern for civilians has mounted as troops advance towards the small jungle area where the remaining rebel forces are alleged by the government to be holding thousands of non-combatants as "human shields".
Cluster bomb claims
The United Nations reported at least 52 people were killed in a single shelling on Tuesday evening - though it did not say who was responsible - and said cluster bombs had been used in the attack.
The government denied it had cluster bombs, which release many smaller explosives over a wide area when they explode, but said the Tigers were known to have them.
There was no immediate reaction from the Tigers, who have been asked by international backers of Sri Lanka to consider terms of surrender and avoid further bloodshed.
The United States, European Union, Japan and Norway asked them to lay down their arms and take part in a political dialogue to end Sri Lanka\'s vicious civil unrest which has claimed over 70,000 lives since 1972.
"Nothing could be as ridiculous as this," Defence Secretary Rajapakse told the Island newspaper.
\'Unconditional surrender\' sought
"Nothing short of unconditional surrender of arms and cadres could bring an end to the offensive."
Rajapakse, President Mahinda Rajapakse\'s younger brother, said Tuesday\'s statement by the quartet known as the co-chairs was a "transparent attempt to save the Tigers".
The co-chairs said the military had cornered the rebels - formally known as the Liberation Tigers of Tamil Eelam - in the island\'s northeast.
"There remains probably only a short period of time before the LTTE loses control of all areas in the north," they said.
The defence secretary stressed there could be no future political role for the Tigers, who are widely predicted to return to guerrilla warfare tactics if they are defeated.
"The international community should not expect the Sri Lankan government to allow the LTTE\'s participation as a political party in a fresh negotiations process after the armed forces crushed its wherewithal to wage war," he said.
Foreign governments have said the bloodshed must end, and thousands of Tamils and their supporters held protests in Chennai, Singapore, Paris, Geneva and Berlin.
Pope Benedict XVI added his voice to the calls to stop the offensive for the sake of what he called "the growing number of innocent victims".
"I make an urgent appeal to the combatants that they respect humanitarian law and the freedom of movement of people," the pope said during his weekly general audience.
A military official said the Sri Lankan air force on Thursday used concentrated aerial attacks to support advancing ground troops who came under fresh attack from the Tigers. There were no immediate reports of casualties.