"If that statement and those accusations are authentic, then it's an issue that should be addressed at the UN, probably at the Security Council, because the UN is the founder of the International Criminal Tribunal (for the former Yugoslavia) in The Hague," Sanader told the press in Vrlika at the 17th anniversary of the local branch of his Croatian Democratic Union party.
Sanader said he could not say more about the matter at the moment, but underlined that this was a "very serious" issue.
The chief prosecutor in the trial of late Serbian leader Milosevic before the ICTY has written to Croatian newspaper Jutarnji List saying that Del Ponte made a deal with Belgrade which it used to conceal the evidence of Yugoslavia's involvement in the 1990s wars in Croatia and Bosnia and Herzegovina.
The New York Times said on Monday that "in the spring of 2003, during the trial of Slobodan Milosevic, hundreds of documents arrived at the war crimes tribunal in The Hague marked 'Defense. State Secret. Strictly Confidential.' The cache contained minutes of wartime meetings of Yugoslavia's political and military leaders, and promised the best inside view of Serbia's role in the Bosnian war of 1992-1995".
But there was a catch. Serbia "obtained the tribunal's permission to keep parts of the archives out of the public eye. Citing national security, its lawyers blacked out many sensitive - those who have seen them say incriminating - pages. Judges and lawyers at the war crimes tribunal could see the censored material, but it was barred from the tribunal's public records," the newspaper wrote.
The decision approving such protective measures came personally from Mrs Carla Del Ponte, Nice wrote in the letter to Jutarnji List.
Lawyers and others who were involved in Serbia's attempt to keep secrets now say that Belgrade clearly defined its goal on that occasion - keeping integral military archives from the International Court of Justice in The Hague, before which Bosnia and Herzegovina had sued Yugoslavia for genocide. Belgrade succeeded in this given that no verdict against Serbia was handed down.
Nice also noted in his letter that he had warned Del Ponte against making any concessions to Serbia.