Cambodia told the UN chief that the tribunal would only be allowed to prosecute four Khmer Rouge leaders who are already in custody. But prime minister Hun Sen says the UN backed court will not be allowed to try another five suspects who are under investigation.
Presenter: Robert Carmichael in Phnom Penh
Ban Ki-moon, UN secretary general; Khieu Kanharith, Cambodian minister of information; Kyung-wha Kang, deputy high commissioner for human rights
CARMICHAEL: Cambodia describes itself to foreign tourists as The Kingdom of Wonder. And over the last two days the UN secretary general Ban Ki-moon might well have wondered why he came.
The UN has long had an interest in Cambodia and numerous UN agencies operate here, including the UN human rights office.
But the outfit with the highest profile is the Khmer Rouge tribunal, a hybrid UN-Cambodian court tasked with trying the movement's senior surviving leaders and those the court considers most responsible for crimes committed during their rule between 1975 and 1979.
The tribunal has battled on through a number of crises over the years, from well substantiated allegations of corruption to allegations of political interference and an ongoing shortage of cash.
Despite its problems, Mr Ban was probably not expecting the conversation Cambodia's prime minister, Hun Sen, had with him at their meeting on Wednesday morning.
There Hun Sen bluntly told Mr Ban that the tribunal's second case - against four senior leaders of the Khmer Rouge - would be its last.
He said the court would not be allowed to prosecute another five people it has been investigating.
It is up to the court and not Hun Sen to decide whom it should prosecute, and his words predictably raised the spectre of political interference, all of which damages the tribunal.
But later on Wednesday the minister of information, Khieu Kanharith, said Hun Sen would simply prefer that those cases were scrapped.
KHIEU KANHARITH: We don't say forbidden because you cannot dictate, you cannot impose your will on the court.
CARMICHAEL TO KHIEU KANHARITH: So the prime minister is just saying he would far prefer if cases three and four did not go ahead.
KHIEU KANHARITH: This is right, yes, this is right. Because it would be a failure.
CARMICHAEL: I asked Ban Ki-moon on Thursday during a very brief press conference before he left the country what he thought Hun Sen had meant to say.
BAN KI-MOON: I had a good discussion on this matter twice with the prime minister, Hun Sen, and also the deputy prime minister, and I can tell you that the government of Cambodia is committed to the completion of the process. The United Nations will discuss this matter with the international community members, particularly donors. That's what I can tell you at this stage.
CARMICHAEL: The entire sentence hinges on the phrase 'committed to the completion of the process'. Late on Thursday, Mr Ban's spokesman said by email that meant 'completion of the judicial process and of the court's mandate'. As to specific cases, he has said, 'that's a matter for the court to decide independently'.
Time will tell how that plays out in practice.
The other bombshell Hun Sen delivered was his demand that the UN shut its Cambodian human rights office and sack Christophe Peschoux, the UN's human rights head in Cambodia.
Since the presence of a human rights office is a matter of agreement between the UN and a member state, the government will likely eventually get its way with closing the office.
The UN's deputy high commissioner for human rights, Kyung-wha Kang, is travelling with Mr Ban.
She told me on Wednesday evening that the discussion with Hun Sen revolved around an array of issues, one of them human rights.
KYUNG-WHA KANG: And the prime minister made his reply, which was a little bit of a surprise, I should say the tone, but it opens up the door for further discussions, and again on the issue of a person, we do not wish to go into the details. And yet obviously the government has a different view to the high commissioner on her representative here, but I am sure we will find a way to discuss this issue of the representative and also the issue of the office here on more constructive terms.
CARMICHAEL: Possibly. But not if Khieu Kanharith is to be believed. The minister says the days of the UN human rights office here are numbered since it only accuses the government of wrongdoing and acts as a mouthpiece for the opposition.
All in all then, this trip to Cambodia was probably not the success Ban Ki-moon had hoped for.