International Criminal Court judges rejected Thursday a prosecution request to issue an arrest warrant for a commander of a brutal militia that has terrorized eastern Congo for years.

Judges said in a written decision that Prosecutor Luis Moreno-Ocampo's May 15 request did not go into enough detail of the alleged crimes of Sylvestre Mudacumura, a field commander in the Democratic Forces for the Liberation of Rwanda, which is also known by its French acronym FDLR.

The judges wrote in a harshly worded rejection that the request did not provide "proper counts or any other kind of accompanying description" of the allegations.

Moreno-Ocampo alleged that Mudacumura was responsible for crimes against humanity including murder, rape and torture in North and South Kivu provinces.

Thursday's decision came just a day after Moreno-Ocampo received another setback in his efforts to prosecute crimes in Congo.

On Wednesday, the court rejected his appeal against a decision to drop charges against another prominent member of the FDLR, Callixte Mbarushimana.

The FDLR is accused of unleashing savage attacks on civilians in the North and South Kivu provinces of Congo as a "bargaining tool" to win power back in Rwanda. Mbarushimana was accused of orchestrating an international campaign of propaganda and extortion to force Rwanda to accept the return of the rebels who had fled the country after its 1994 genocide.

But appeals judges upheld a pretrial panel's ruling that the evidence — including propaganda that Mbarushimana produced from his Paris apartment — wasn't strong enough to lead to a conviction.

Mbarushimana faced 11 charges of war crimes and crimes against humanity, but always maintained his innocence. He was arrested in October 2010 and released in December.

Prosecutors did not immediately comment on Thursday's decision.