The battles came amid a major escalation in fighting in the northern jungles in recent weeks. Senior government officials say they aim to capture rebel-held territory and crush the Tamil Tigers in a bid to end more than two decades of warfare on the Indian Ocean island.
The worst of the fighting broke out Tuesday afternoon when rebels attacked military positions near the Adampan section of the Mannar district just south of rebel-held territory, said Brig. Udaya Nanayakkara, the military spokesman. Soldiers fought back in a battle that killed 20 Tamil Tiger fighters and three troops, he said.
In other fighting, a group of soldiers crossed over the front lines in the Jaffna peninsula north of rebel territory in the morning, in an attack that destroyed a bunker and killed five rebels, Nanayakkara said. Troops in the area launched an attack against a second bunker Tuesday afternoon, killing at least four rebels, the military said.
The increasingly common attacks on Tamil Tiger fortifications appeared to be an aggressive new tactic in the military's fight against the separatists.
Nanayakkara denied this, saying the troops were simply responding to attacks from the bunkers.
"When you are getting disturbed from those locations, you have to take action," he said.
Other fighting along the Jaffna front lines killed three rebels and one soldier, Nanayakkara said. And a clash Tuesday evening along the front lines in Muhamalai, killed another soldier, he said.
The military also announced Tuesday that eight rebels had been killed a day before in battles in the Vavuniya and Mannar districts south of rebel territory, bringing the rebel death toll for Monday to 24.
Rebel spokesman Rasiah Ilanthirayan could not be reached for comment.
Each side routinely exaggerates the other's casualties and plays down its own. Independent verification is difficult because access to the battle area is restricted.
With the violence raging, international human rights groups have called for the United Nations to send a monitoring mission, a demand the government rejects as a violation of its sovereignty.
The rebels have fought since 1983 for an independent homeland for ethnic minority Tamils after decades of discrimination under governments controlled by the Sinhalese majority. More than 70,000 people have been killed in the conflict.