Sudan has signed a ceasefire with the two main rebel groups in western Sudan, to allow foreign aid to reach refugees. But the government backed Arab militias continue to drive non-Arab villagers from their homes throughout the Darfur region. The government denies any connection with the militias, but it is clear that the militias have new weapons and frequent contact with army officers. The Arab and non-Arab tribes have long feuded over control of land. The government is dominated by Islamic conservative Arabs, which is reluctant to move against Arab tribal militias operating in the south and west.