Colombo  - Sri Lankan President Mahinda Rajapaksa on Wednesday expressed confidence of defeating Tamil separatist rebels within days and ending the civil war they have been fighting against the government for the past three decades.

"I am confident that in a few days, we will decisively defeat the terrorist force that many repeatedly kept saying was invincible," Rajapaksa said in an address to the nation marking the 61st anniversary of the island nation gaining independence from Britain.

Rajapaksa said the Liberation Tigers of Tamil Eelam (LTTE) had been on the verge of achieving its goal of dividing the country and establishing a separate state in the northern and eastern parts of majority-Sinhalese Sri Lanka.

He urged the country's ethnic groups to unite and urged refugees to return home in view of the expected peace.

The president, who was elected in 2005 on a security platform, praised the armed forces and police for their achievements in defeating the LTTE.

Rajapaksa's comments came as government troops were fighting to retake the final rebel strongholds in the Mullaitivu district in north-eastern Sri Lanka.

The army on Tuesday said it had restricted the rebels to an area of about 275 square kilometres.

Local and international concerns about civilians in the war zone has been mounting as about 250,000 people are believed to be trapped there, according to the United Nations and the International Committee of the Red Cross.

The government accused the rebels of using civilians as human shields and preventing them from leaving the area while the LTTE charged the army with indiscriminately shelling the area.

According to the army, at least 12,000 LTTE rebels and 3,5000 soldiers have been killed since the start of the latest campaign against the LTTE in August 2006, but those figures cannot be confirmed independently because the military denies journalists and independent monitors access to the conflict zone.

Wednesday's military parade took place among tight security. The centre of the capital, Colombo, was closed down, and more than 10,000 police deployed for the event. (dpa)