THE Khmer Rouge tribunal's foreign co-prosecutor, Robert Petit, has filed a "statement of disagreement" against his Cambodian counterpart  over whether the UN-backed court should seek to try more people for their alleged roles in the regime's 1975-79 reign.

According to a statement released Monday by the Extraordinary Chambers, Cambodian prosecutor Chea Leang and Petit disagree over whether new judicial investigations into crimes "by certain persons considered to be senior leaders of the Khmer Rouge" are appropriate.

Chea Leang declined comment, but Petit told the Post Monday that he believed more arrests are justified and had initiated the disagreement process.

Once both prosecutors submit statements to the court's pretrial chamber, at least four judges will make a decision in a closed-door hearing, court rules state.

"Based on preliminary evidence and an interpretation of the court's mandate, I believe that further investigations are warranted," Petit said.

He did not specify how many arrests he believed are necessary, but observers have speculated that at least six formerly high-ranking regime officials have been targeted.  

Heather Ryan, a court monitor for the Open Society Justice Initiative, told the Post in an email that proceeding with cases against additional suspects was important for the credibility of the court.

"Limiting the number of accused to the existing five fails to fully exercise the jurisdiction of the court ...  and risks making the court look like it is supporting a show trial of only the most notorious" regime members, she wrote.