Six of the country’s most prominent civic groups called on the UN-backed Khmer Rouge tribunal to ensure its integrity is safe from corruption.

In a joint statement to the courts, the groups called for a credible, independent method for dealing with alleged corrupt practices, following allegations made since 2007 that staff on the Cambodian side of the hybrid court pay kickbacks to senior government officials.

“We wish for them to have a solid mechanism for independence and to reinforce credibility,” said Thun Saray, president of the rights group Adhoc, which was among the six organizations to issue the statement.

The UN and Cambodian sides have not agreed on a unified mechanism for handling the allegations. The government argues that complainants should be identified; the UN insists on anonymity.

“We are concerned that the mechanism does not have enough efficiency to combat corruption in the court,” Thun Saray said.

Meanwhile, the Pre-Trial Chamber of the court postponed a decision on whether more indictments should be investigated. Judges met Friday to settle a dispute between the UN and Cambodian prosecutors.

International prosecutor Robert Petit has said six more suspects could be charged with atrocity crimes, but his Cambodian counterpart, Chea Leang has echoed concerns of Prime Minister Hun Sen, saying more indictments could destabilize the country.

“We are working,” said chamber judge Prak Kim San. “No result.”