BANGKOK, Thailand (AP) _ A Thai security official said Tuesday that a group of up to 600 Cambodian refugees would be returned to the control of the communist Khmer Rouge, but the U.S. State Department said that wouldn't happen.

The refugees fled the Khmer Rouge camp of Kaiche after it was heavily shelled in mid-April and traveled a few miles to Sok Sann camp, run by the non-communist Khmer People's National Liberation Front, or KPNLF.

The Khmer Rouge, the largest guerrilla group fighting Vietnamese forces in Cambodia, wanted the refugees returned to Kaiche. But the U.N. Border Relief Operation and the International Committee of the Red Cross, which have reported widespread human rights violations in Khmer Rouge camps, insisted the refugees be allowed to choose where to live.

The Thai official, speaking on condition of anonymity, said that as a ''compromise,'' the military decided the refugees should be moved to Site 8, the only Khmer Rouge camp where the guerrillas have allowed aid officials to give refugees full medical and other services. Site 8 is north of Kaiche, which is along the Cambodian border and in Thailand's eastern Trat province.

He could not say when the transfer would take place.

State Department spokeswoman Margaret Tutwiler said in Washington that the Thai government confirmed to U.S. officials that the refugees will be allowed to remain in non-communist resistance camps. She said this followed strong appeals from U.S. officials to Thailand that the refugees not be returned to Khmer Rouge control because their safety could not be assured.

''The United States goverment continues to be strongly opposed to the return of these Cambodians to Khmer Rouge control,'' she said.

A Western relief official, also speaking anonymously, called the Thai decision a ''face-saving'' move in which the military would avoid criticism for returning the refugees to Kaiche yet still continue support for the Khmer Rouge.

''The refugees should have individual choice,'' he said. ''Some people have families in Sok Sann and they should stay in Sok Sann. Some have families in Site 8 and they should go to Site 8. Some people have reasons to flee Khmer Rouge control and they should not be sent to Khmer Rouge control.''

The Khmer Rouge ruled Cambodia from 1975 until Vietnamese forces invaded and ousted it from power in late 1978. Washington says 2 million people, a fourth of the population, were executed or died of famine in the Khmer Rouge's attempt to impose radical agrarian communism.

The Khmer Rouge fled to the border, established camps just inside Thailand and allied itself with guerrillas of the KPNLF and of Prince Norodom Sihanouk. Violations reported in Khmer Rouge refugee camps included forcing children to porter arms through mine fields and denying people emergency medical treatment.

Western aid officials have been barred from Kaiche. The flight from Kaiche was one of the largest escapes from a Khmer Rouge camp in years, one relief official said.

The refugees fled after gunners inside Cambodia rained heavy shells on Kaiche and nearby Ta Luan camp. Relief officials believe hundreds of people were hurt, but the Khmer Rouge refused to allow any to be evacuated to outside hospitals.