The refugees are held at Cambodian run camps
The Cambodian Government says it will allow more than 900 Vietnamese hill tribe people to be moved from border refugee camps to the United States.
The decision ends weeks of speculation about the future of the Montagnard people, who fled Vietnam's central highlands a year ago following protests over land and religious rights.
The camps are run by Cambodia with assistance from the United Nations refugee agency, the UNHCR, which will be involved in the resettlement programme.
Cambodia wants refugee camps closed and warns that future illegal migrants will be arrested and deported.
History of emigration
Its government had been caught between its obligations under the Convention on Refugees and Vietnam's insistence on the return of people it calls illegal border crossers.
Now, Prime Minister Hun Sen says Cambodia wants to end the suffering of the Montagnards in the camps by allowing them to be moved to a third country.
It is not the first time that Montagnards have turned to America for shelter.
The fall of the central highlands was a turning point in the Vietnam War.
Thousands who had sided with the US fled the provincial capital of Buon Ma Thuot and surrounding areas as communist forces bore down on Saigon.
In the late 1980s, others migrated to the US under the orderly departure programme.
Today, America has a large population of Montagnards, particularly in the state of North Carolina.
Families may follow
Hanoi labels many of them hostile forces and says US-based separatists are trying to destabilise the highlands.
Most of the people still in Cambodia's camps are men who have left families in Vietnam.
Some may yet choose to return home. For those who do not, the US ambassador to Cambodia, Kent Wiedeman, says America could consider applications for their families to join them.
If Hanoi lets them go, that could swell the number of Montagnards going to America to several thousand.
Hanoi denies that Vietnam discriminates against its ethnic minorities.
The communist authorities say observers are ignoring their efforts to reduce poverty and improve social conditions in the highlands.
But the UN, diplomats and other independent observers have been prevented from verifying Hanoi's statements about its good intentions.