A UN agency has called on Thailand to release 149 Hmong refugees from Laos who have been detained in Thailand for more than a year.
Some 9,000 Hmong refugees from Laos live in Thailand
The UN High Commission for Refugees (UNHCR) said they had all been offered asylum in other countries.
The UNHCR is particularly concerned about the 90 children in the group - five of whom were born in detention.
The Hmong are a minority hill tribe people who claim they have been persecuted in Laos.
The 149 refugees were rounded up in Bangkok in December 2006 and have been held at the Nong Khai Immigration Detention Centre, close to the Laos border, ever since.
Thailand came close to repatriating them forcibly in early 2007 but backed down following international pressure and a hunger strike from some detainees.
Some said they would "rather die" than return to Laos.
The UNHCR said the group has now spent 400 days in detention without any of them having committed a crime.
HMONG IN LAOS
Ethnic group that often complains of marginalisation in Lao society
Took the side of the US in the Vietnam War - and say they are persecuted because of it
Many still live in jungles
Small numbers say they are fighting rebel insurgency
Thousands have fled to Thailand in recent years
US took in 14,000 Hmong recently, but has no plans for taking more
It said the refugees were allowed out of their cells for three hours each day and that the "overall conditions still fall well short of international standards".
The UNHCR's Erika Feller said there was no basis for their detention.
"They should be allowed to take up the offer already made to them to leave Thailand and start to live productive lives and have a future in other countries," she said.
About 9,000 ethnic Hmong refugees are living in Thailand, many of them in refugee camps.
They say they face persecution in Laos, because they or their ancestors supported the US military in the Vietnam War.