Tamil Tiger rebels blew up an army bus in Sri Lanka's capital Thursday, killing at least one soldier, just hours after the guerrillas said they had stormed a naval base and killed 35 sailors.
The escalation in violence came days after the Tigers, who have been fighting for a separate state since 1972, vowed they would never return to peace talks unless the government halted a military campaign against them.
Initial investigations suggested that a Tiger suicide bomber on a rigged motorcycle had rammed into the army bus, but a police spokesman said the bomb could have been detonated by remote control.
"We are now looking at the possibility that the motorcycle was placed by the side of the road and detonated as the bus passed," the spokesman said from the scene of the blast, just outside the capital's sea port.
National Hospital spokeswoman Pushpa Soysa said the army driver of the bus died from his injuries and another soldier was in a critical condition. Four soldiers and three civilians were brought in for treatment.
The attack came just hours after the Liberation Tigers of Tamil Eelam (LTTE) staged a pre-dawn raid on a strategic naval base at Delft, an islet off the northern Jaffna peninsula.
"During a search operation, we found 35 bodies of Sri Lankan sailors and weapons," Tiger spokesman Rasiah Ilanthiriyan told AFP by telephone from the rebel-held Wanni region.
Four rebels were killed in the operation, he said, adding the Tigers had captured two anti-aircraft guns, two machine guns, one rocket-propelled grenade launcher and eight automatic assault rifles.
Sri Lanka's defence ministry, however, said in a statement that the attack was resisted and that 18 rebels were killed for the loss of four sailors.
"Intercepted LTTE communications revealed that 18 Sea Tiger cadres, including four leaders, had been killed and another large number injured," the ministry said.
Each side is known to discount casualty figures claimed by the other. There is no independent verification because foreign truce monitors have little or no access to combat areas.
The Tigers meanwhile accused the military of setting off a mine attack inside rebel-held territory Thursday and killed a civilian woman and her brother.
"An internally displaced woman and her brother were killed on the spot by a Sri Lanka army Deep Penetration Unit (DPU)-triggered Claymore mine targeting their motorbike," an LTTE statement said.
Further north, local officials said a curfew had been imposed in Delft, which has a small population of fishermen.
In another attack, the Tigers killed three constables from the police homeguard unit in the northern district of Vavuniya early Thursday, the defence ministry said.
It said troops had also killed two Tiger rebels in a separate confrontation in the east of the island late Wednesday.
Fighting has intensified across the island in recent days, and on Wednesday the International Committee of the Red Cross said it had pulled its staff away from northern frontlines dividing government and rebel forces.
Sri Lankan troops and Tamil rebels have been locked in combat following the breakdown of a 2002 Norwegian-arranged truce.
Nearly 5,000 people have died in the past 18 months, and the 35-year-long separatist conflict has claimed 60,000 lives.
The Tigers' political wing on Sunday said a return to peace talks was out of the question if government attacks continued.
Tit-for-tat attacks have left the February 2002 truce in tatters, and both sides are apparently convinced there is a military solution to the conflict.