At least five people have been killed in a mine attack in north-eastern Sri Lanka blamed on Tamil Tiger rebels, local military officials say.
Bloodshed is increasing, putting strain on a fragile truce
The explosion in the port town of Trincomalee was apparently aimed at a navy patrol, officials said.
The military also blamed the rebels for a shooting in the same region in which two people were killed and three hurt.
The violence follows recent attacks that have strained a fragile ceasefire and thrown peace talks into doubt.
Four Tamil civilians and a navy official were killed in the blast in a residential part of Trincomalee, the authorities say.
Eight others, including four sailors, were said to have been injured.
"The people who did it are not humans, there are small children and ladies around," Kamalachandran, a local resident whose daughter was hurt in the blast, told the Associated Press.
Separately, the Sri Lankan navy said boats from the Sea Tigers - the rebels' naval wing - had attacked one of its vessels off the coast of Trincomalee.
"They have opened fire and attacked our Dvora," Reuters quoted navy spokesman DKP Dassanayake as saying, referring to the Israeli-built Dvora fast-attack craft.
"We retaliated in self-defence."
Five sailors were wounded in the exchange of fire, the navy said.
Truce under threat
The BBC's Dumeetha Luthra in Colombo says the attacks are a sign that bloodshed is once again increasing.
International mediators have been scrambling to save a truce between the rebels and the government, which has been threatened by a fresh outbreak of violence this month.
Last Tuesday, a rebel suicide bomber killed at least 11 people at a military base in Colombo, triggering government air raids, which killed at least 12 people.
More than 60,000 people have been killed in Sri Lanka since the Liberation Tigers of Tamil Ealam (LTTE) launched its campaign for a separate state in the north and east of the country in 1983.