NEW : South Sudan becomes Africa 's newest state . It recognizes the sovereignty of the Sudan , within the 1956 borders . The referendum to split was part of a 2005 peace deal aimed at ending the decades of violence between the two sides . Those borders put the contested town of Mara in the north . A new U.N. military mission will step in .
NEW : South Sudan becomes Africa 's newest state . It recognizes the sovereignty of the Sudan , within the 1956 borders . Those borders put the contested town of Mara in the north . A new U.N. military mission will step in .