A Norwegian envoy was set to arrive in Sri Lanka on Friday in efforts to prevent a resumption of full-scale civil war after an escalation in clashes between the military and Tamil Tiger rebels in the north and east.

On Thursday, the Tamil rebels and government forces blamed each other for artillery attacks on three schools in a northeastern town that killed 18 residents sheltering there. The government-held town, Muttur, has been the scene of the worst fighting since the two sides signed a now-battered cease-fire agreement in 2002.

The latest round of violence was sparked by a rebel move to shut down a reservoir and cut off water to government-held villages. The military responded with airstrikes and a ground assault.

Norwegian envoy Jon Hanssen-Bauer, who is scheduled to arrive from Oslo Friday, will meet with Sri Lankan government leaders and travel to the rebel stronghold of Kilinochchi over the weekend in an effort to settle the dispute, embassy spokesman Tom Knappskog said Thursday.

The Tigers, meanwhile, said they were preparing to hand over, through the Red Cross, the bodies of about 40 Sri Lankan soldiers killed in the Muttur fighting, the pro-rebel TamilNet Web site reported, quoting rebel spokesman Rasiah Ilanthirayan.

There was no immediate confirmation from the humanitarian agency.

The government has acknowledged the death of just eight of its soldiers in Muttur.

Both sides claimed to have the upper hand in the fighting in Muttur, but with the area closed to outsiders there was no way to independently verify the situation.

A military spokesman, Maj. Upali Rajapakse, said the rebels were responsible for the attacks on the schools — but TamilNet blamed government forces for at least one attack, in which 10 people died. The rebels, who often issue statements through TamilNet, have made no statements about the other two schools.

Rajapakse said one government soldier was killed Thursday in Muttur and five more were wounded in a gunbattle with the rebels. No further details were available.

TamilNet reported that the guerrillas had seized control of Muttur, but the military refuted that report.

"The town is under our control," chief government spokesman Keheliya Rambukwella told The Associated Press.

The latest surge in fighting came after dozens of rebels infiltrated Muttur, near the strategic northeastern port town of Trincomalee, overnight Wednesday, setting off intense gunbattles that continued into Thursday evening.

Rajapakse said casualties suffered by the rebels Thursday were not immediately known.

A two-decade civil war killed about 65,000 people before the 2002 cease-fire that left parts of the north and east under rebel control. While the agreement remains officially in effect, escalating violence since December has killed at least 900 people, half civilians.