By Arthur Asiimwe KIGALI, July 6 (Reuters) - Rwanda has formally asked France to hand over a man accused of involvement in the Rwandan genocide who was arrested last month as he tried to enter the United States, officials said on Friday. Isaac Kamali, the holder of a French passport, was arrested at Philadelphia airport and returned to Paris where he remains in custody. He is on Rwanda's wanted list of genocide suspects submitted to Interpol. "We have formally sent an extradition request to have him brought back to Rwanda to stand trial," Martin Ngoga, Rwanda's chief prosecutor, told Reuters. "We have sent the request through the Belgian embassy here and we can only hope French authorities honour it." Kigali severed diplomatic ties with Paris in November in protest at a French magistrate's call for President Paul Kagame to face prosecution over the killing of a former president. Kigali closed its embassy in Paris and expelled the French ambassador from Rwanda. Kamali was a senior member of Rwanda's former ruling party, which is blamed for orchestrating a 100-day genocide in 1994 in which 800,000 minority Tutsis and politically moderate Hutus were killed. Kamali faces charges of genocide and crimes against humanity. He is accused of masterminding killings, looting and destruction of Tutsi property in Nyabikenke, southern Rwanda.