The Thai government yesterday proposed that any trial of two Khmer Rouge defectors should limit its scope to the "killing fields" years when the Maoist group imposed its brutal rule from Phnom Penh.
The statement came amid growing pressure on neighbouring Cambodia for an international tribunal, which some analysts say could prove embarrassing to countries once involved with the notorious guerrillas.
"Other elements are extraneous," a senior Foreign Ministry spokesman, Mr Kobsak Chutikul, said, stressing that the decision whether to try the defectors was Cambodia's alone.
During the late 1970s the Khmer Rouge ruled Cambodia, imposing on the country a murderous agrarian dictatorship which claimed the lives of up to two million people.
The Khmer Rouge nominal leader, Mr Khieu Samphan, and the ideological figurehead, Mr Nuon Chea, defected to the government side on Christmas Day two decades after being driven out of Phnom Penh by a Vietnamese invasion force.
The Cambodian Prime Minister, Mr Hun Sen, condemned Thailand last week for giving sanctuary to the pair and forcing him to accept their defections rather than have them stand trial.
Thailand quickly denied the allegation, but hinted that the country may have once been more welcoming of the Maoist rebels.
Mr Kobsak said yesterday it was up to Cambodia whether it wanted a trial and the procedures that would govern it, but added that any international tribunal would need the go-ahead from the UN Security Council.
Close aides to the former rebels have been defiant, saying any move towards a trial would force the pair to reveal uncomfortable details about their past.
"A trial will not benefit the nation," said one aide, Mr Long Norin, warning that not everyone would wish to hear the Khmer Rouge leader's account of their brutal regime.
"It is a very complicated issue: if they push for an international tribunal we will dig up the past and present. We will prepare our things to say, then we will go to The Hague together for trial," he said.
China, which is a permanent member of the Security Council and now remains silent over Cambodia, was once a key ally of the Khmer Rouge.
Critics say that following their flight they were propped up, in the form of a three-way Khmer Rouge-dominated rebel coalition, by the United States and Thailand to check the spread of Vietnamese communism.
Cambodia's King Norodom Sihanouk, who was part of that coalition, reacted angrily last week to a cartoon in a Thai newspaper which depicted him as welcoming the rebels back.
"As for our Thai neighbours, nobody ignores what they have done in favour of the Khmer Rouge for decades. They have no anti-Khmer Rouge lessons to give to my family which, with our people, have suffered so much from the unspeakable cruelties and injustices of the Khmer Rouge," said the king, who lost several family members during Khmer Rouge rule.
Meanwhile in Paris yesterday the former UN secretary-general, Dr Boutros Boutros-Ghali, justified his meeting in Phnom Penh with Mr Khieu Samphan, and called the resulting flap "a storm in a teacup".
Dr Ghali was responding to the French daily Le Monde, which sharply criticised his statement that trying Khmer Rouge leaders for genocide would be interference in Cambodia's "internal affairs".
In a written statement the former UN chief said: "If the international community wants to judge the Khmer Rouge, it should assume that responsibility, and I fully support it."