MOSCOW, JAN. 2 -- Soviet agents questioned three U.S. prisoners-of-war in Vietnam in 1978, five years after Vietnam claimed to have returned all living POWs, a former KGB official said today. He said a dozen or so Americans were kept in Vietnam long after the war ended.

Retired Maj. Gen. Oleg Kalugin, who headed Soviet counterintelligence during that time, said he was in charge of the project, although he did not conduct the interviews and has never been in Vietnam.

"There were at least three of them, as far as I remember," Kalugin said in an interview with the Associated Press. "I would not remember their names. I recall simply that one was a naval officer, the other was from the CIA and the third I think was an Air Force pilot."

He said the three "were the remnants -- several, a dozen or so -- who stayed in Vietnam long after the war was over. Why the Vietnamese kept them, I don't know."

{In Washington, the Pentagon issued a statement saying that U.S. Embassy officials in Moscow interviewed Kalugin in November and December about the episode and "his claims are being investigated fully and actively." The statement said investigators are pursuing his offer to put them in touch with the Soviet official identified as leading the interrogation.}

In November, a high-ranking North Vietnamese defector, former army Col. Bui Tin, told the U.S. Congress that Soviet agents interrogated American POWs, but only during the war. He said he did not believe that any American POWs remained in Vietnam after 1973.

Also in November, a U.S. official running the search for POWs in Hanoi told a special Senate committee he believed as many as 10 U.S. servicemen remained in captivity at the end of the Vietnam War. Garnett Bell, head of the U.S. office for POW-MIA affairs in Hanoi, said he believed some of the men had been killed.

Kalugin was forced to retire from the KGB in 1990 after criticizing some agency practices. He was later elected to the now-disbanded Soviet parliament.

His latest disclosures were reported today by the Daily News in New York, but it was not the first time he has made such a statement. In its Oct. 27 editions, the Los Angeles Times quoted Kalugin as saying that Soviets had interrogated American POWs in Vietnam during and after the war.

His story has changed since that interview, however. He told the Los Angeles Times that the questioning occurred in 1976; in his interview with the Daily News and with the AP today, he said it occurred in 1978.

Kalugin told the AP that the KGB agent who led the interrogation in Vietnam was Oleg Nechiporenko, a former official of the Soviet consulate in Mexico City. He said he would try to contact Nechiporenko to speak about the interrogations. Kalugin told the Daily News he believed two of the three POWs later returned to the United States.

Kalugin, who said he has revealed the POW disclosures in a book he has written, noted the U.S. Senate had invited him to Washington to testify about his statements, "although I don't really have much to dd to what I've said already."

Kalugin also asserted that no Americans POWs had been brought to the Soviet Union by its ally, Vietnam, after the war. "I absolutely exclude the possibility," Kalugin said. "For either political or even practical purposes, it makes no sense."

Direct U.S. involvement in Vietnam ended in 1973. The war ended in 1975 with a North Vietnamese victory.

There have been scattered reports of U.S. prisoners sighted in Southeast Asia since the war ended. More than 2,000 Americans are still listed as missing in Vietnam, Cambodia and Laos.