By Guy de Launey
BBC News, Phnom Penh
The government's enthusiasm for the tribunal has often been questioned
Disagreements have arisen at the Khmer Rouge tribunal in Cambodia over whether more people should be investigated.
The UN-appointed prosecutor asked judges to intervene after he and his Cambodian counterpart were unable to move forward.
It is the first time that international and Cambodian officials have had a public disagreement since the tribunal started two years ago.
The court is looking into the deaths of some two million people in the 1970s.
The filing of an official "statement of disagreement" suggests the tribunal may have a serious problem.
WHO WERE THE KHMER ROUGE?
Maoist regime that ruled Cambodia from 1975-1979
Founded and led by Pol Pot, who died in 1998
Abolished religion, schools and currency in a bid to create agrarian utopia
Up to two million people thought to have died from starvation, overwork or execution
Five former Khmer Rouge leaders are in custody awaiting trial on charges of crimes against humanity.
And international co-prosecutor Robert Petit believes several more people should be investigated.
But he has been unable to convince his Cambodian colleague, Chea Leang. And asking the judges to intervene indicates that any attempts to reach a compromise have failed.
There has always been the potential for the tribunal to hit such a problem.
Although it is backed by the United Nations, it is actually a Cambodian court. And the government's enthusiasm for the process has frequently been called into question.
Many senior figures in the current administration were themselves formerly members of the Khmer Rouge.
And as the number of prosecutions rises, so does the chance of embarrassment - or worse - for people in high places.
But organisations monitoring the tribunal have said that proceeding with more cases is vital for the court's credibility.