COLOMBO, Sri Lanka — A suspected Tamil rebel boat exploded off Sri Lanka’s east coast yesterday, killing at least three insurgents, as clashes between rebels and soldiers in the north left four guerrillas dead, the military said.Separately, army troops found the bodies of 15 separatist Tamil Tigers killed in battles this week as the military launched a major push to flush rebels from the island’s volatile east.

The explosion occurred in the sea off Nilaveli, a coastal village in eastern Trincomalee district, when navy boats fired at an advancing rebel boat, said Lt. Col. Upali Rajapakse, a senior military officer.

He said it was too early to say whether the boat was destroyed, adding that the navy believed at least three insurgents were killed. A woman’s body has been recovered from the waters, he said.

Rebel spokesman Rasiah Ilanthirayan said he by telephone from guerrilla stronghold of Kilinochchi that he was unaware of any boat blast.

Yesterday, insurgents attacked an army foot patrol near Muhamalai, a border post dividing government and rebel-held areas in Jaffna peninsula, Rajapakse said.

He said soldiers returned fire and later found the bodies of two rebels.

Earlier yesterday, troops fired at insurgents near Point Pedro town, also in Jaffna, triggering a pre-dawn clash, Rajapakse said. Two rebel bodies were found later. The army did not suffer casualties, he said.

The military said soldiers found the bodies of 15 rebels and nearly a hundred anti-personnel mines when searching territory captured from the guerrillas this week.

That brings the estimated rebel death toll to 45 in Tuesday’s clashes in the Thoppigala area between the army and the separatist Tamil Tigers, an official at the Defence Ministry information centre said.

Sri Lankan soldiers have driven out the guerrillas from many of their eastern bases and Thoppigala is believed to be their last stronghold.

Peace broker Norway meanwhile announced that international backers of Sri Lanka’s stalled peace process would meet in Oslo on Tuesday to discuss how to halt the bloodshed.

Representatives from the United States, Japan and the European Union will “explore ways and means in which the group, as a whole or as individual countries, can continue helping the parties to cease violence and return to the negotiating table,” a Norwegian foreign ministry statement quoted top peace envoy Erik Solheim as saying.

US Assistant Secretary of State Richard Boucher, Japanese envoy Yasushi Akashi, EU Director General Andreas Michaelis and James Morran of the European Commission will participate in the meeting, the ministry said.

The latest violence comes amid a worsening separatist conflict in Sri Lanka that has killed more than 5,000 people since December 2005, rendering a five-year-old Norway-brokered cease-fire useless.

Even though the two sides have largely ignored the cease-fire as battles between the two escalate, neither side has officially withdrawn from the agreement.

Tamil Tiger rebels have fought the government since 1983 to carve out an independent homeland for the country’s ethnic Tamil minority who have suffered decades of discrimination by successive ethnic Sinhalese-controlled governments.

More than 70,000 people have been killed in more than two-decades of violence.