More than 3,000 people have fled renewed violence in Sudan's troubled Darfur province in the past few days, the United Nations says. It was not clear who was behind the latest fighting near the town of Zam Zam in North Darfur, a UN report said. Last week, the UN said that the Sudan government had failed to stop the Arab Janjaweed militias from attacking black African villagers in Darfur. More than a million people have fled their homes in the past 18 months.