( AFP )- Heavy fighting raged Sunday in northern Sri Lanka where Tamil Tiger rebels said they lost a key leader, as Norwegian-led monitors began pulling out before the formal end of a tattered truce.
The defence ministry said at least 36 guerrillas were killed and a soldier wounded in fighting since Saturday along the de facto border marking rebel-held territory.
Among the men killed was a top Tamil Tiger intelligence official, the ministry said, confirming a report on the pro-rebel website Tamilnet.com that a top leader holding a rebel rank of colonel had been killed.
The Liberation Tigers of Tamil Eelam (LTTE) said they lost the head of an intelligence unit, Shanmuganathan Ravishankar , who was killed along with three other Tigers when a military unit infiltrated rebel territory.
Two other suspected rebels died early Sunday after setting off hand grenades, apparently killing themselves to avoid capture by troops in the northern Jaffna peninsula, the defence ministry said.
Sri Lankan officials have denied carrying out attacks inside rebel-held territory, but said there had been heavy long-range exchanges of fire in the region since the truce was formally declared dead last week.
The fresh clashes came as the Norwegian-led Sri Lanka Monitoring Mission said it was winding down its operations before the February 2002 truce brokered by Norway formally ends on January 16.
The government last week scrapped the truce agreement, which automatically also ends the monitoring mission, and gave the mandatory two weeks' notice to pull out.
President Mahinda Rajapakse's top advisor on the peace process quit Sunday, after the government abrogated the Oslo-brokered truce amid mounting international concern that the country could see even more intense fighting.
Jayantha Dhanapala , a diplomat and former candidate for the post of UN secretary general who was appointed as peace advisor in December 2005, said he was quitting for "personal reasons," in a statement released by his office.
Close confidants of Dhanapala said he was embarrassed by the turn of events, with the government pressing for a military victory after scoring several battlefield successes against the rebels last year.
In the capital Colombo, the government on Sunday heightened already tight security arrangements.
Motorists said all vehicles entering or leaving the city of 650,000 people were being checked one by one, causing long queues and traffic snarls.
Police said 75,000 individuals and 28,000 vehicles were searched during a three-hour operation, with nearly 200 people detained and eight vehicles impounded.
"Those who were not able to prove their identity were detained for questioning," police spokesman N. K. Illangakoon said.
According to the latest government figures, 74 rebels and three soldiers have died in fighting since the start of the year.
There was no comment from the rebels, who are fighting for an independent homeland for minority Tamils in the island's north and east.
Independent verification of casualty figures is not possible as journalists are not allowed into rebel-held areas. Both sides are known to make sharply varying casualty claims.
Tens of thousands of people have died since the conflict erupted in 1972.