The Ituri district saw some of the most intense violence in the Congo and the background is described in this HRW Report:
The war in Ituri is a complex web of local, national, and regional conflicts that developed after a local dispute between Hema and Lendu was exacerbated by Ugandan actors and aggravated by the broader international war in the DRC. National rebel groups such as the Congolese Liberation Movement (Mouvement pour la Libération du Congo, MLC), the Congolese Rally for Democracy-Liberation Movement (Rassemblement Congolais pour la Démocratie-Mouvement de Libération, RCD-ML) and the Congolese Rally for Democracy-Goma (Rassemblement Congolais pour la Démocratie-Goma, RCD-Goma) have supported local militia in their conflicts as a way to expand their own base of power in the DRC transitional government or perhaps even to derail negotiations. These national groups, as well as local ethnic groups in Ituri, have been and, in some cases, still are supported by the Ugandan, Rwandan and DRC governments. Ituri is now the battleground for the war between the governments of Uganda, Rwanda and the DRC which have provided political and military support to local armed groups despite abundant evidence of their widespread violations of international humanitarian law.