Sri Lanka yesterday bowed to international pressure and announced plans to close the internment camps that are home to more than 130,000 people locked up since the end of the country's bitter civil war six months ago.

Two days after the United Nations' top humanitarian official, Sir John Holmes, urged Sri Lanka to allow those inside the camps to leave, the Government in Colombo announced internees would be set free from their barbed wire enclosures from December 1.

Basil Rajapaksa, the brother of Sri Lankan President Mahinda Rajapaksa and one of his key advisers, said the camps would close completely by January 31.

The camps and the detention of hundreds of thousands of people after the end of the fighting have become a diplomatic embarrassment to the Sri Lankan Government, which had hoped to capitalise on its success in bringing the 26-year civil war to an end.

Instead, it found itself on the receiving end of international condemnation over the detention of noncombatants and mounting criticism of the conditions inside the camps, which remained squalid.

Domestic political considerations may also have sped up the releases.

President Rajapaksa received an unexpected political setback this month when Sarath Fonseka, the head of the Army and the man who plotted the defeat of the Tamil Tigers, announced that he was quitting to "fight for democracy".

He is widely expected to mount a challenge to the President in forthcoming elections, possibly as early as next April, and his popularity could mean a much closer fight than the incumbent was expecting.

In a farewell letter to troops Fonseka pledged to work to restore human rights, media freedom, social justice, ethnic unity and peaceful coexistence.

"I want to assure you that I will commit myself to protect democratic freedoms which we are rapidly losing," he wrote.

Sri Lanka had acknowledged the international clamour for action on the camps when it pledged in September to release all the detainees by January, but until recently officials had continued to stress the problems faced by the Government in dealing with the inmates.

One official said that concerns remained about whether many of those held had played an active part in the Tamil Tiger military campaign or had offered support to the terrorists. He also cited security problems which made it difficult to return some people to their villages, particularly the presence of minefields. Many of the estimated 1.5 million mines have yet to be made safe.

The decision received a qualified welcome from the humanitarian agency Unicef, whose spokeswoman Sarah Crowe said it was "to be welcomed without any doubts" but cautioned that those who had been locked up for months would need time to adjust.