By Charles Haviland
BBC News, Colombo
Some 300,000 ethnic Tamils are being held in camps in Sri Lanka
Amnesty International has urged Sri Lanka's government to set free hundreds of thousands of Tamil war refugees currently detained in camps.
The human rights group says their continued internment is a breach of international human rights covenants.
In a report, Amnesty says donor nations have not been doing enough to demand an end to their arbitrary detention.
In response, a Sri Lankan minister said it was "mischievous to talk of rights in the absence of security".
The Amnesty report is a wide-ranging critique of the conditions in which some 300,000 Tamils are now living after surviving the horrors of the war's final weeks.
But its main focus is on the linked issues of liberty and freedom of movement.
Under the International Covenant on Civil and Political Rights, freedom of movement would cover people's right to leave the camps and choose where to live.
Liberty refers to their right to move freely in and out of the camps as long as they live there.
Amnesty says that in denying them both these rights, the Sri Lankan government is in effect detaining them "without charge or trial" - which Amnesty says also breaks international law.
The report, entitled "Unlock the camps in Sri Lanka", includes testimony from some refugees now abroad, or their relatives.
One describes how the Tamil Tiger rebels beat up people trying to escape their zone, and also how the authorities later prevented a woman taking her injured 13-year-old granddaughter with her when she got permission to leave their camp.
The government says it needs time to screen everyone, except young children and the elderly, for possible links with the Tigers.
But Amnesty says the government must stop treating the camp-dwellers as suspected former combatants. They must be released, it says.
Sri Lankan Foreign Secretary Palitha Kohona told the BBC that it was "mischievous to talk of rights in the absence of security".
He said the "vast majority" of Sri Lankans were delighted that the conflict was over and that the government must ensure the country did not "regress into the dark ages".