Sri Lanka's Defense Ministry says a roadside bomb killed five soldiers and wounded another Friday, as they traveled in the country's north.
In a separate incident, officials say mortar fire from Tamil rebels late Thursday killed eight civilians in the east.
The Associated Press reports the rebels blame government shelling for the civilian casualties, which happened as the two sides fought near a rebel stronghold.
Fighting between government forces and Tamil rebels has recently intensified.
A naval battle off Sri Lanka's eastern coast Thursday killed at least 16 rebels, one day after government troops captured a key rebel base in the east, district of Batticaloa.
Monday, the rebels staged their first-ever air strike, using a small plane to bomb an air force base near the capital, Colombo.
The government and rebels signed a ceasefire in 2002, but renewed fighting in the past 18 months has killed about 4,000 people.
Some information for this report was provided by AFP and AP.