Sri Lankan forces sank a Tamil rebel boat as it approached a strategic harbour in the island's north, rebuffed an attack on an army patrol and killed a suspect guerrilla in the east, the military said on Saturday.
Mounting attacks have raised fears of a return to all-out civil war on this tropical island off the southern tip of India.
Late on Friday, the Tamil Tiger rebels' sea wing appeared to be about to attack a strategic port in the northern Jaffa Peninsula, a navy spokesman said.
"We first made some warning shots, but the boat continued and then we fired and the boat caught fire and sank," Commander DKP Dassanayake said.
It was not immediately know how many people were on the rebel boat that sank, nor if there were any rebel casualties. "Our men had to fire because the boat was advancing toward Kankesanturai harbour."
No non-navy boats are allowed in the waters because it is designated a "high security zone," Dassanayake said.
The harbour is a main point of entry for supplies to an estimated 40,000 troops stationed in the region.
A pro-rebel website, TamilNet, called the incident a "sea fight," and reported that two boats were seen burning, although it did not identify the vessels.
Dassanayake said no navy vessels were damaged. On Saturday, the army killed a suspected Tamil guerrilla as he tried to attack a checkpoint with a hand grenade in northern Mannar district, 220 kms north of the capital, Colombo, said Brig Prasad Samarasinghe, an army spokesman.
Separately, suspected Tamil Tigers using small arms and mortars attacked an army road clearing patrol in Muttur, a small town in eastern Sri Lanka, Samarasinghe said.
"We also retaliated using mortars," he said, adding that no soldiers were wounded in the clash near the port city of Trincomalee, 215 kms northeast of Colombo.
The rebels did not immediately comment on Saturday's attacks. More than 700 people have been killed in violence since April, despite a 2002 cease-fire agreement between the government and the rebel group.
The Tigers have been fighting since 1983 to carve out a separate homeland for Sri Lanka's 3.2 million minority Tamils.