CAIRO (AP) — A Sudanese doctors’ union says the death toll from tribal violence between Arabs and non-Arabs in West Darfur province has climbed to at least 83, including women and children. The clashes grew out of a fistfight between two people on Friday and continued till Sunday morning. The violence also wounded at least 160. Local authorities have imposed a round-the-clock curfew on the entire province to contain the situation. The clashes pose a challenge to efforts by Sudan’s transitional government to end decades-long rebellions in areas like Darfur. The violence comes two weeks after the U.N. Security Council ended the joint U.N.-African Union peacekeeping force’s mandate in Darfur.