Colombo  - Heavy fighting between government troops and Tamil rebels in northern Sri Lanka has claimed the lives of more than 140 from both sides and left more than 33 soldiers missing, a military spokesman said Thursday.

The fighting took place Wednesday around Muhamalai, 390 kilometres north of the capital as government troops pushed into rebel controlled areas following a pre-dawn attack by the rebels.

Military spokesman Brigadier Udaya Nanayakkara said that at least 100 rebels and 43 soldiers have been killed in 11 hours of fierce fighting, the biggest single clash since government troops renewed offensive attacks against rebels since April 2006.

He said that a search operation has been launched along the battle lines for the missing 33 soldiers, but a pro-rebel Tamilnet website said that at least 30 bodies of soldiers have been recovered by the rebels of the Liberation Tigers of Tamil Eelam (LTTE).

Nine bodies of the rebels have been found by the army, he said.

Both the army and the rebels were planning to exchange the bodies recovered through the International Community of the Red Cross (ICRC).

Brigadier Nanayakkara said that 160 soldiers and 196 rebels were injured in the confrontation.

Most of the injured soldiers have been flown to Colombo for treatment while the bodies of soldiers also have been brought to the capital for funeral ceremonies.

The military claimed that during the offensive troops recaptured some of the rebel controlled areas, but the rebels have made a counter claim that they took control of army controlled areas and seized some of their weapons.

"Soldiers have been able to capture the first line of bunkers of the (rebels) Tigers in Muhamalai. LTTE terrorists came and attacked our forward line on Wednesday morning, we have retaliated and captured about 400 to 500 metres of LTTE area in Muhamalai," Brigadier Nanayakkara was quoted as saying in a defence ministry statement.

However, the military earlier said they had launched a fresh military offensive ahead of the forward defence lines and thereafter came under attack from the rebels.

Government troops have been trying to recapture rebel held areas in the north during the past four months and have vowed to do so by the end of the year.

The fighting in the north has so far claimed the lives of more than 2,500 rebels and at least 300 security personnel before Wednesday's clashes. (dpa)