A new United Nations report says Sudan has not disarmed Arab militias or stopped attacks against civilians in the strife-torn Darfur region. The report for the UN Security Council did note some progress, but called for more foreign troops to go to Sudan. The Sudanese ambassador to the UN described the report, which did not recommend any sanctions, as balanced. Up to 50,000 people have been killed in Darfur, following a campaign by Arab militias against black Africans. The violence has exacerbated a humanitarian crisis which has seen one million people driven from their homes. Ambassador Elfatih Erwa said Sudan had not been able to do all that the UN wanted because of what he called environment and circumstances. In a BBC interview, Sudan's Minister of State for Foreign Affairs, Najib Al-Kheir Abd-Al-Wahab, said security was a complicated process, but he insisted that the Sudanese government could maintain law and order in Darfur. The UN's envoy to Sudan, Jan Pronk, presented the report to the Security Council, and said attacks continued and "the vast majority of armed militias has not been disarmed". The report says despite "some progress" in improving security and helping the distribution of humanitarian relief, "the government of Sudan has not been able to resolve the crisis in Darfur, and has not met some of the core commitments it has made". "Similarly, no concrete steps have been taken to bring to justice or even identify any of the militia leaders." The BBC's Stephen Gibbs, at the UN in New York, says it is being seen as the definitive report to date on the situation in Darfur. At the end of July the UN called on Sudan to rein in the Janjaweed militia blamed for atrocities in the region, or face unspecified measures. The UN gave itself 30 days to report on whether the demands had been met. There has been argument within the UN over whether Sudan should face sanctions. The report, prepared by Mr Pronk on behalf of UN Secretary General Kofi Annan, does not mention sanctions but calls for a "substantially increased international presence" in Darfur as quickly as possible. The UN and the African Union have been working on a plan for the current small observer mission to be expanded to a force of 3,000 troops and 1,100 police, with a wider role. So far, Nigeria and Rwanda have each sent about 150 troops to Darfur to guard ceasefire monitors. Peace talks between the Sudanese government and rebels from the Darfur region are continuing in Abuja. The Darfur crisis erupted when two African rebel factions took up arms against Khartoum in February 2003, alleging they were being ignored by the Arab government. The UN's emergency relief co-ordinator says life for many thousands of people in Darfur region remains desperately precarious. Jan Egeland said civilians still faced the threat of "rampant rape and killings" by pro-government militias. On Wednesday the UN World Food Programme (WFP) appealed for $12m (£6.7m) to help feed tens of thousands of young children and pregnant mothers it fears will otherwise die. Other aid agencies have also been stepping up their programmes - Unicef says it has vaccinated up to 50,000 children against polio in Darfur, sometimes reaching remote areas by camel and donkey. Meanwhile, a group of six aid workers, missing since Saturday in rebel-controlled territory in the north of Darfur, were said by the WFP to have been released unharmed on Wednesday.