The secret document, which is reported to have been written by General Tran Van Quang when he was the North Vietnamese army deputy-chief of staff, was discovered by a US university researcher in Communist Party archives in Moscow. The report has cast a cloud over prospects for a rapid normalisation of ties between Vietnam and the United States.
The report to the Communist Party politburo puts the number of US PoWs held by Vietnam in 1972 at 1,205; however, only 368 were ever officially acknowledged before the 1973 Paris peace accords.
The former US national security adviser Zbigniew Brzezinski told the New York Times he believed it was likely that Hanoi had shot 'hundreds of American officers' in a Vietnam War massacre comparable to the Katyn woods slaughter of the Second World War, when more than 4,500 Polish officers were killed in a forest near Smolensk by Soviet secret police.
Mr Brzezinski told Stephen Morris, the researcher who discovered the document, that he thought it was authentic, the New York Times said. Mr Brzezinski told the newspaper that after studying the document, he believed that 'the great likelihood is that the Vietnamese took hundreds of American officers out and shot them in cold blood, in a massacre like the one in the Katyn woods'.
Mr Brzezinki noted that he had no concrete evidence to support his belief the US prisoners were massacred. But he said he was struck by three things in the document: its style, which corresponded to other reports of a similar nature; the number 1,205, which he said corresponded to the approximate number of men the United States expected to be returned; and what he called 'the Katyn-like classification system'.
'At the Katyn woods they specially selected members of the Polish aristocracy,' said Mr Brzezinski, an expert on Soviet affairs. 'And here you have the same kind of ominous pattern, with prisoners being classified according to their degree of intransigence in refusing to condemn the war. They say the officers come from rich families, which explains their attitude.'
He speculated that Vietnam concealed the existence of the PoWs after the peace agreement because they feared that Washington would renew fighting, or because Hanoi planned to seek financial reparations, the New York Times said. 'I think the chances are very small that any more than a few might have been kept alive until now,' he said.
Vietnam yesterday rejected the report and denied that it was still holding any prisoners. Vietnam's ambassador to the United Nations denounced it as a 'forgery'. 'Some people in the United States still have the Vietnam syndrome,' he said. 'They can't overcome it and therefore they try to use all sorts of things to obstruct the improvement of relations' between Washington and Hanoi.
President Clinton has asked General John Vessey, the presidential emissary for prisoners of war missing in action, to travel to Vietnam next week to evaluate Vietnam's co-operation in the investigations.
In Moscow, a Foreign Ministry spokesman, Sergei Yastrzhembsky, said Russia would continue to do everything it could 'in the search for documents that might shed light on the truth on this issue'.