Meanwhile, four civilians have been shot dead in separate incidents in Jaffna peninsula and in the neighbouring districts of Vavuniya and Batticaloa since late Thursday, military officials and the defence ministry said.
The Tamil rebels are fighting for an independent homeland for the Tamil minority.
More than 60,000 people have been killed in Sri Lanka's bitter ethnic conflict since 1972.
Troops attacked concentrations of the Liberation Tigers of Tamil Eelam (LTTE) in Trincomalee district but there were no immediate reports of casualties.
"There were some Tiger movements noticed and we brought down long-range weapons on them," a military official in Trincomalee, 260 kilometres (160 miles) northeast of the capital, said.
The guerrillas were possibly poised for an attack on government troops who recently wrested control over an irrigation canal in the district after intense fighting, he said.
The shelling occurred despite peacebroker Norway's announcement earlier this week t