Secretary General Kofi Annan has fired the chief administrator and deputy prosecutor of the U.N. war crimes tribunal for Rwanda after an internal investigation found widespread mismanagement and incompetence, the United Nations announced today.

U.N. spokesman Juan-Carlos Brandt said Annan had accepted the resignations of Andronico Adede of Kenya, the chief administrator, and Honore Rakotomanana of Madagascar, the deputy prosecutor, because "continuation in their posts would not be in the interests of the United Nations and of the work of the tribunal in a case involving human tragedy of incalculable proportion."

The tribunal was established by the Security Council two years ago to try persons implicated in the massacre of more than half a million Tutsis and moderate Hutus during the tribal strife that engulfed Rwanda in 1994. Several months ago, the United Nations was rocked by complaints from Western staff members and media reports that the tribunal's functioning had descended into chaos because the administrators had given jobs to unqualified friends, relatives and lovers, discriminated against non-Africans and misused tribunal funds and equipment.

The situation posed the first serious test for Annan, who took office Jan. 1 promising to subject the United Nations to top-to-bottom reform. Western diplomats and private organizations in the human-rights field warned that failure to take stern action would be viewed in the world community as a sign of weakness and indecisiveness. But Annan, a native of Ghana who was elected as the candidate of Africa, also was aware that some African governments deeply resented the idea that a housecleaning in the U.N. bureaucracy should begin with the largely African Rwanda tribunal staff.

Two weeks ago, a report by Karl Paschke, the U.N.'s equivalent of an inspector general, said that while there was no evidence to substantiate charges of corruption and racism, his investigators had found massive mismanagement and waste at every level of the tribunal. Noting that "not a single administrative area . . . functioned effectively," Paschke left Annan little room for leniency.

Paschke recommended discharging Rakotomanana. But he left to Annan a decision about Adede, noting the tribunal had been hampered by inadequate administrative and personnel support from U.N. headquarters in New York. The tribunal's headquarters in Arusha, Tanzania, is headed by Adede, and Rakotomanana directed a prosecution branch office in the Rwandan capital, Kigali.

After Paschke's report was made public, many non-African judges and others associated with the tribunal privately contacted the secretary general's office and the media to repeat earlier charges that administrators hobbled their work through bureaucratic interference. Despite Paschke's findings, some asserted anew that the tribunal was rife with racism and nepotism.

Brandt said that following talks with Annan, Rakotomanana and Adede had submitted their resignations "accepting that the best interests of the United Nations and the tribunal are overriding concerns."

Named as Adede's replacement was Agwu Ukiwe Okali of Nigeria, a graduate of the London School of Economics and Harvard law school, who has been serving in the U.N. habitat office in Kenya. A new deputy prosecutor will be named later.

The tribunal so far has indicted 21 people, and now is conducting its first trial against Jean-Paul Akayesu, a former Rwandan mayor charged with inciting the public to murder.