Violence in Sudan's West Darfur region has forced 57 000 people to flee their homes over the past month, including 11 000 who have crossed into Chad, the UN refugee agency said Tuesday.In Chad, UNHCR spokesperson Babar Baloch said the refugees were scattered in several villages along the border."The conditions are dire. Most are staying in the open or under makeshift shelters, with little protection from the elements. Food and water are urgently needed," he said.Baloch said that UNHCR and other organisations were providing some humanitarian assistance but added: "The rate of refugee arrivals risks outpacing our capacity".UNHCR estimates that the number of refugees fleeing to Chad from West Darfur "could reach 30 000 in the coming weeks as tensions persist," he said.The latest fighting in West Darfur was between an African tribe called Masalit and an Arab tribe called Rizeigat - two groups which have often fought over the years since the Darfur conflict first erupted in 2003.The violence, which left dozens dead, is the latest example of fighting in Darfur between peasant farming tribes, which are mostly non-Arab, and nomadic pastoralists, who are mostly Arab."UNHCR teams on the ground are hearing accounts of people fleeing after their villages, houses and properties were attacked, many burnt to the ground," Baloch said.He said UNHCR wanted "the international community's support for the transitional government of Sudan in addressing the root causes of the conflict in Darfur".Darfur - made up of five states - spiralled into conflict in 2003.The Darfur fighting broke out when ethnic minority rebels took up arms against the Arab-dominated government of now ousted president Omar al-Bashir, whom they accused of marginalising the region.The conflict left around 300 000 people dead and displaced 2.5 million others, the UN says.Although the unrest has reduced greatly in recent years, there are still regular outbreaks of violence.