By Opheera McDoom KULBUS, Sudan, Nov 5 (Reuters) - Sudan has failed to disarm proxy militias in Darfur as promised under a May peace deal, and government forces did not act to protect civilians in an attack last week that killed at least 50, a new U.N. report says. The attack occurred on Oct. 29 near Jabel Moun, in an area where both rebel and government forces are present. The report, seen by Reuters on Sunday, said 26 children were among 50 people killed in militia attacks on at least four villages. It said most of the 7,000 civilians living in the srea had fled their homes. "At the very least, the attacks demonstrated the government of Sudan's continued failure to disarm militia in Darfur and, at worst, its use of militia forces that target civilians," it said. The report was prepared by the Office of the U.N. High Commissioner for Human Rights on the basis of witness accounts, and is due to be released shortly. Arab militias, known locally as Janjaweed, are blamed for a widespread campaign of rape, murder and pillage in Darfur that Washington calls genocide. Khartoum denies genocide and any link to the Janjaweed, but it does admit having armed some militias during the 3-1/2-year conflict to fight the mostly non-Arab rebels. It denies giving any current support to militias. Just to the north of where the attacks took place, Janjaweed work together with government forces in the border town of Tine, and share their base. The army calls them border intelligence forces, but the raggedly dressed youths are mostly Arabs from Darfur. The U.N. report said authorities had known for a month prior to the attack about a build-up of Arab militias in the area, but took no action to prevent the attack, similar to hundreds of others during a conflict that experts say has killed 200,000 and forced 2.5 million to flee their homes. "Soldiers at a nearby army base at Goz Mino did not take action to protect the civilians," the report added. It said witnesses had reported that some of the attackers were wearing new military khaki uniforms, and three of them wore Sudanese armed forces insignia. Under a peace deal signed in May by only one of three negotiating rebel factions and the government, the government vowed to disarm the Janjaweed by Oct. 22. But a new alliance of rebels who reject the deal has renewed hostilities. The report said the international community had to provide more equipment and support to a struggling African Union force that is failing to stem the violence in Darfur. The force of around 7,000 is poorly equipped and does little more than monitor the attacks.