U.N. prosecutors have called for a retrial in the case against Kosovo’s former prime minister.

Ramush Haradinaj was acquitted last month of war crimes against Serbs during the Kosovo conflict.

Prosecutors at the Yugoslav war crimes tribunal appealed parts of the acquittal of Haradinaj and two other ethnic Albanians. They say witness intimidation undermined their case and judges did not allow enough time to compel witnesses to testify.

Friday’s appeal calls for a retrial for all three suspects on six of the 37 charges they faced.