The government of Laos has rejected charges by the State Department that it is hindering efforts to locate and care for refugee children deported from neighboring Thailand. The children from the Hmong ethnic group have been separated from their parents for nearly two months and their whereabouts are not officially known.

The Lao government reacted with dismay after the State Department called for it to disclose the whereabouts of 27 refugee children. The children, from the Hmong ethnic group, were deported secretly from Thailand in December. The U.S. urges Vientiane to allow international aid agencies to provide care for the children.

Government spokesman Yong Chantalangsy said the children were sent to Laos without the knowledge of his government.

"Since we are not aware and notified at all on this issue, we were not involved in separating those children and we were not involved at all in the deportation of those children, therefore the responsibility is not on our side. So I am surprised why the pressure should be put on our country," he said.

He says his government has been told that the children were sent to Bolikhamxay Province, east of Vientiane, but he indicated their exact whereabouts is not known. He said officials are looking into the matter.

International sources who asked to remain anonymous say the children are in the custody of Lao security forces and there are concerns about their health. International aid groups say Thai authorities seized the children after they were found outside their camp in northeastern Petchabun province.

The groups say the children were transported to Lao territory without being registered with the Lao government. No reason has been given for this action.

The Thai government has not publicly responded to the reports, but officials in Bangkok say they are dealing with the issue.

The Hmong ethnic group in Laos and Vietnam backed the U.S. government during the Vietnam War and hundreds of thousands of them fled to Thailand after the Americans withdrew in 1975.

Over the years, many found new homes in other countries. Last year the U.S. government accepted 15,000 Hmong, saying this would be the last group to be taken. But thousands more remain, many of them more recent immigrants who crossed into Thailand believing that they, too, would be resettled in the United States.

The Thai government considers them illegal immigrants and says it has the right to deport them. But Laos considers those who leave the country without approval to have relinquished their citizenship and will not let them return. The issue has repeatedly strained ties between the two governments.