The chief prosecutor of the United Nations war crimes tribunal has formally appealed the acquittal of former Kosovo Prime Minister Ramush Haradinaj.

In the appeal, prosecutor Serge Brammertz called for a retrial on several charges against Mr. Haradinaj and two co-defendants. He said widespread intimidation and fear prevented key witnesses from fully testifying in the trial.

Brammertz said the court denied the prosecution a fair trial and did not grant it enough time to compel testimony from prosecution witnesses. He said a retrial must include their testimony.

Last month, the tribunal acquitted Mr. Haradinaj and an associate, Idriz Balaj, of war crimes during the Kosovo conflict of the 1990s. The court sentenced a third defendant, Lahi Brahimaj, to six years in prison for cruel treatment of detainees at a prison camp run by the ethnic Albanian guerrilla group, the Kosovo Liberation Army (KLA).

All three men held senior positions in the KLA.

Prosecutors had indicted the three on 37 counts, including involvement in the murder, persecution, rape and deportation of ethnic Serbs in Kosovo areas under their control in 1998.

Mr. Haradinaj was the highest-ranking Kosovo Albanian politician to go on trial before The Hague tribunal. He stepped down as Kosovo's prime minister in 2005 after being indicted.

Some information for this report was provided by AFP, AP and Reuters.