(Adds ex-president's aide paragraph 12) By Harro ten Wolde AMSTERDAM, May 22 (Reuters) - The International Criminal Court's prosecutor launched an investigation on Tuesday into allegations of killing and rape in the Central African Republic during the armed conflict of 2002 and 2003. "We believe that grave crimes falling within the jurisdiction of the Court were committed in the Central African Republic," ICC prosecutor Luis Moreno-Ocampo said. The alleged crimes in the Central African Republic, one of the world's poorest countries which has suffered decades of instability, occurred during a conflict between the government and rebels, which peaked in 2002 and 2003. "Attacks against civilians followed a failed coup attempt; there emerged a pattern of massive rapes and other acts of sexual violence perpetrated by armed individuals. Sexual violence appears to have been a central feature of the conflict," the prosecutor's office said. His office will investigate allegations of sexual violence against at least 600 reported victims. At this stage, the investigation is not directed at any particular suspect but will try to identify the individuals with the greatest responsibility, the prosecutor said. But a local human rights official said last month that a top court in the Central African Republic had referred former President Ange Felix Patasse and Congolese former rebel leader Jean-Pierre Bemba to the ICC on war crimes charges. Charges were brought against Patasse, who is living in exile in the West African state of Togo, and Bemba, as well as against suspected Chadian mercenary leader Abdoulaye Miskine, in September 2004. But the appeals court in Bangui declared itself incompetent to handle the case. BEMBA BACKS INQUIRY Bemba, who sent his militiamen to help Patasse in 2002-2003 when Patasse was fending off rebel attacks on the capital Bangui, denied any responsibility for the alleged crimes. "Physically, I wasn't there (in Central African Republic), as you know," Bemba told Reuters from his temporary home in southern Portugal. Bemba said he was in favour of an inquiry into the 2002-2003 events in Central African Republic, where the intervention of his militia did not stop Patasse from being overthrown in a coup by Francois Bozize, the current president. In the Togolese capital Lome, where Patasse is living in exile, an aide said the ex-president was willing to testify before the ICC. "There are no worries on our side," said Martial Bety-Maracen, foreign minister under Patasse. According to the prosecutor's office victims described being raped in public, gang raped and abused in the presence of family members. Many were shunned by their communities and stigmatised. Some were infected with HIV during the attacks. Human Rights Watch welcomed the official investigation and said it would help to end decades of impunity. The ICC, the world's first permanent war crimes court, started work in 2002 and is now supported by 104 nations, although still not by Russia, China and the United States. It is a court of last resort and intervenes in situations only when national judicial authorities are unable or unwilling to conduct genuine proceedings. This investigation is the court's fourth, and all are in Africa. The ICC has already indicted suspects for conflicts in the Democratic Republic of Congo, Uganda and Sudan's Darfur region. (Additional reporting by Joe Bavier in Kinshasa, John Zodzi in Lome)