Human Rights Watch has accused the Sri Lankan government of not having any concrete plans to resettle displaced Tamils, who have been held for months at locations like the Manik Farm displaced persons camp pictured here. (Kirsty Wigglesworth/Associated Press)

The Sri Lankan government should immediately resettle more than 280,000 displaced Tamils who have been held in camps through the closing stages of a 25-year civil war, a prominent human rights group said Tuesday.

"Keeping several hundred thousand civilians who had been caught in the middle of a war penned in these camps is outrageous," said Brad Adams, Asia director at Human Rights Watch. "Haven’t they been through enough? They deserve their freedom, like all other Sri Lankans.”

The displaced are ethnic Tamils who fled their homes at the height of a civil war between government forces and the separatist group known as the Liberation Tigers of Tamil Eelam. The war ended in May after the government concluded a final, punishing offensive against the Tamil Tigers.

During the offensive, the government moved a number of civilians living in the northern rebel-controlled territory to temporary camps.

Foreign diplomats and aid workers fear that the camps are actually internment camps where the displaced people are being held indefinitely.

The Sri Lankan government has said that it will aim to resettle most of the displaced within six months. But Human Rights Watch dismissed that timeline, saying the government has yet to provide concrete settlement plans, and few of the displaced have been told when they might be able to leave.

The group's entreaties come a day after Eric Schwartz, U.S. assistant secretary of state for refugees, similarly pressed Sri Lanka to speed up resettlement and recovery efforts.

After pledging $8 million US in aid aimed at hastening the resettlement process, Schwartz said Monday "there remain burdensome limitations on access to those camps for those international humanitarian organizations and others who are in a position to ameliorate the conditions faced by these victims of conflict."

Sri Lanka has been reluctant to allow humanitarian groups unfettered access to the camps. President Mahinda Rajapaksa said in May that likely pro-rebel "infiltrators" among the refugees meant high levels of security at the camps were needed.

He also suggested that some humanitarian groups may have a pro-Tamil agenda. He said in May that as the security situation improved, there would be no objections to aid "from organizations that were genuinely interested in the well-being" of the displaced Tamils.

With files from The Associated Press