The Hmong are asylum seekers who fled Laos for Thailand and other Western countries after the Communist regime took power in Laos in 1975. The UN has determined some of these individuals who may need protection.

"The Secretary-General regrets that these deportations have taken place in the face of appeals from the United Nations High Commissioner for Refugees and despite the availability of third country resettlement solutions for those recognised as refugees," Ban's spokesperson said.

"He (Ban) urges the Governments of Thailand and the Laos People's Democratic Republic to take all necessary steps to respect the rights of those concerned and to facilitate humane solutions," he added.

Since then, many returned home voluntary but other stayed back for over thirty years fearing persecution having participated in the conflict that consumed the country in the sixties and seventies.

A number of Hmong were enlisted by Central Intelligence Agency (CIA) to fight against the communist-nationalist Pathet Lao during the Secret War in the sixties, and later many of them settled in the United States.

The UN Refugee Agency (UNHCR) has not been given access to the 4000 refugees deported from one camp in the northern province of Petchabun. The 158 deported from another camp in the northeast were recognised by the agency as refugees.

"UNHCR is also calling on the Government of Thailand to provide details of assurances received from the Government of the Lao People’s Democratic Republic within the framework of a bilateral agreement between the two governments concerning the treatment of the returned Lao Hmong," the agency said in a news release.

"UNHCR has asked to be informed of steps taken by the Government of Thailand to ensure that commitments made under this framework.

While the Hmong fear that they will face retribution in Laos while Prime Minister Abhisit Vejjajiva has stated that Thailand had received assurances that refugees will be in no danger once they return home are effectively honoured."