COLOMBO: Sri Lanka on Sunday severely criticised Western nations for calling for a ceasefire that would end its military offensive against the Tamil Tiger rebels before a complete victory has been secured.

The rebels asked Britain and France to broker a truce, but the government has vowed to fight on until the guerrillas, who have been campaigning for an independent Tamil homeland for 37 years, have been crushed.

International concern has focused on the fate of 50,000 civilians thought to be trapped inside the last patch of territory held by the Tigers, and 100,000 people held in government camps after fleeing the fighting.

"Never did history unmask the hypocrisy and the sanctimony of the Western powers than (it has in) their behaviour towards Sri Lanka during recent times," the defence ministry said in a statement on its website.

It accused unidentified Western nations of making "ridiculous demands" on the government, including offering an amnesty to the rebels and allowing the Tiger leaders to be rescued -- as well as agreeing to a ceasefire.

Britain's Foreign Minister David Miliband and his French counterpart Bernard Kouchner left Sri Lanka on Thursday after urging Colombo to stop the fighting and allow humanitarian workers access to the conflict zone.

The ministry statement contrasted the stance taken by "Western powers" with what it said was "whole-hearted support" given to the Sri Lankan government by a long list of countries such as China, India, Japan and Russia.

"But for their understanding on our plight and the trust they placed in us, we would never have been able to come this far in our battle against terrorism," it said.

The Liberation Tigers of Tamil Eelam (LTTE) said in a letter to the British and French ministers that they wanted an immediate ceasefire to end the bloodshed.

"We are ready to engage in the process to bring about a ceasefire and enter into negotiations for an enduring resolution to the conflict," the Tigers said in the letter, which was e-mailed to news organisations on Sunday.

It came a day after the pro-rebel Tamilnet website said 64 civilians were killed in a shell attack against a makeshift hospital in the remaining patch of coastline still held by the Tigers. The military denied the charge.

Sri Lanka on Saturday rejected satellite imagery issued by the United Nations in support of allegations that the military had shelled an area the government itself had designated a no-fire zone.

It said the allegations, based on UN aerial images posted on the UNOSAT website, had "no scientific validity" unless there was verification on the ground.

The pictures showed craters which were formed inside the zone between February 15 and April 19, the day before the army breached the Tigers' defences and civilians started to pour out.

"The imagery is fairly clear and shows the time, so anybody can study and compare them," the head of the mapping unit at UNOSAT, Einer Bjorge, told the Al Jazeera television network.

He said the pattern of the craters would have required air power.

Sri Lanka has consistently denied it used heavy weapons against civilian populated areas and last week announced it had ordered the military not to use heavy calibre weapons and aerial strikes.

A special envoy sent by Japan, which is Sri Lanka's main foreign aid donor, wrapped up a three-day visit on Saturday by calling for non-combatants caught up in the violence to be protected.

Yasushi Akashi said the Tigers must allow all civilians out of the conflict area, and said the government must also improve conditions in the camps where the displaced Tamil civilians are being held.