A breakaway faction of the Tamil Tigers attacked a base of the mainstream guerrillas in the northeastern port district of Trincomalee, killing at least eight, military sources said, citing intercepted rebel radio communication.

There was no immediate word from the rebels but similar clashes on Sunday killed at least 10 members of the Karuna breakaway faction and eight on the main Tiger rebel side, according to the military.

Bombings and attacks over the past month killed at least 200 people but Colombo has been pressing peacebroker Norway and aid donors to help bring the Tigers to the table, the government's top official handling the peace bid said.

"We are optimistic. I am an optimist," Palitha Kohona told AFP late Monday.

"We hope the LTTE (Liberation Tigers of Tamil Eelam) will come for talks in Switzerland at the earliest. We are awaiting responses to the proposals we have made."

Colombo and the Tigers failed to keep an April 19 date to discuss ways of saving their truce. The Tigers asked for a five-day postponement and later put off the negotiations indefinitely, citing logistical and security concerns.

At the root of the problem is a dispute over transporting Tiger leaders for consultations from the island's east to the north where the main guerrilla leadership is located.