The Democratic Republic of Congo's justice minister Monday became the first government official to attend a hearing at the International Criminal Court, over alleged war crimes by an ex-militia chief. Emmanuel-Janvier Luzolo, accompanied by three Congolese officials, was seen taking his place in the tribunal chamber for a hearing on a challenge by indicted ex-militia chieftain Germain Katanga facing trial in The Hague. Noting that his presence marked the first time that a state had been represented at the tribunal, Luzolo underlined the 'manifest willingness' of his country to 'cooperate with the court to fight against impunity'. Katanga is charged with war crimes and crimes against humanity, including using child soldiers, murder, rape ad sexual slavery. He had filed a motion in February asking the ICC to rule the case inadmissible, arguing that the ICC could only intervene if national courts were unwilling or unable to investigate and try war crimes suspects. According to his lawyer, David Hooper, Congolese authorities had investigated Katanga in 2006. The DR Congo government said that it had asked the ICC to look into Katanga back in March 2004. The public hearing on Monday is designed to canvass the issue with all parties involved. Katanga, 31, and co-accused Mathieu Ngudjolo Chui, 38, are scheduled to go on trial before the ICC on September 24. Charges against the men arise from a joint attack on the village of Bogoro, in the DR Congo's mineral-rich Ituri region in February 2003, by the two militias of which they were allegedly the leaders. 'This affair is not the subject of an open investigation in the DRC and falls under the ICC's jurisdiction,' said Congolese Colonel Muntazini Mukimapa, who accompanied the justice minister. 'The DRC did not have the capacity to conduct a thorough inquiry into the crimes committed in Bogoro,' he said. The ICC judges are expected to decide shortly on the issue before Katanga's pre- trial hearing, the court said. The ICC has issued four arrest warrants for war crimes in the DR Congo. The other two accused men are ex-militia chief Thomas Lubanga, on trial in The Hague, and another warlord, Bosco Ntaganda, who is still at large. 