At least 64 passengers of a bus were killed and 39 others, including several children, injured when their vehicle hit a claymore mine planted by Liberation Tigers of Tamil Eelam guerrillas in north central Sri Lanka on Thursday.

The victims were travelling to the town of Kebitigollewa in Anuradhapura district from neighbouring villages to buy provisions when they were ambushed at Yakawela, along a lonely stretch of the road, defence ministry spokesman Prasad Samarasinghe said.

Government Minister Keheliya Rambukwella blamed the attack on the LTTE. "This is a barbaric terrorist attack carried out by the Tamil Tigers," he said.

The bus toppled and was dragged about 25 metre before it came to a halt after being hit by the powerful blast, Samarasinghe said, adding that the casualties were high as the bus was overcrowded.

Rambukwella said 58 people were killed on the spot and 45 others were taken to hospital. Six of the injured succumbed to their injuries, raising to 64 the number of people killed in the attack.

The military responded by launching artillery attacks against suspected LTTE positions in Trincomalee district in the north-east of the island, officials said, adding that artillery barrages and multi-barrel rocket launchers were used to hit Tiger positions at Sampur in the same area.

There were no immediate reports of casualties from the military's retaliatory strikes.

Thursday's attack is the worst against civilians in the latest surge of violence since December despite a truce that has been in place since February 2002, he said.

"No one else would want to a do thing like this," Samarasinghe said, adding, "This is clearly the work of the Tigers."

There has been a spate of bomb attacks against security forces as well as civilians blamed on Tamil Tiger guerrillas.

Despite the truce, there had been a surge in violence since December and official figures show at least 720 people have been killed since then.

The strike comes a day after LTTE leaders returned to the country after abortive talks in Oslo with government officials. The rebels refused to sit at the table with a Sri Lankan delegation for what had been billed as two days of talks to discuss ways of ensuring the safety of Scandinavians monitoring the troubled truce between the two sides.

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