A UN court overturned the war crimes acquittal Wednesday of ex-Kosovo Prime Minister Ramush Haradinaj and ordered that he be retried with two others, citing witness intimidation.

"The appeals chamber ... orders that Ramush Haradinaj, Idriz Balaj and Lahi Brahimaj be retried" on several counts on the initial indictment, presiding judge Patrick Robinson said, and ordered their detention.

Haradinaj, 42, and Balaj, 38, were acquitted in April 2008 on numerous counts of war crimes and crimes against humanity allegedly committed against Serbs and political opponents - including murder, torture and rape.

Coaccused Brahimaj, 40, was convicted of torture and sentenced to six years in jail.

Haradinaj, the most senior Kosovo leader to stand trial at the ICTY, was a commander of the separatist ethnic Albanian Kosovo Liberation Army (KLA) at the time of the alleged atrocities, as was Balaj, who allegedly headed a paramilitary unit known as the Black Eagles.

Brahimaj, 40, was a deputy commander of the KLA and ran the notorious Jablanica prison camp.

The prosecution had sought 25-year prison terms for all three men, but the trial judges found there was insufficient evidence following a trial marked by the reluctance of witnesses to testify, allegedly under pressure of intimidation.

Robinson upheld an appeal by the prosecution against the acquittal of Haradinaj and Balaj, saying the trial chamber had "failed to appreciate the gravity of the threat that witness intimidation posed for the trial's integrity".

"The trial chamber failed to take sufficient steps to counter witness intimidation that permeated the trial," said the judge.

"Given the potential importance of these witnesses to the prosecution's case, the error undermined the fairness of the proceedings and resulted in a miscarriage of justice."

The court also overturned not-guilty findings on various charges against Brahimaj.

Haradinaj and Brahimaj, both dressed neatly in suits and ties, displayed no reaction to the decision. Balaj was not present.