A policeman guards a polling station as an internally displaced woman arrives to vote at ZamZam IDP's camp in Al Fasher, northern Darfur April 12, 2010. Observers on Monday urged Sudan to extend voting in its first open elections in 24 years after thousands of ballots were cast incorrectly and polling faced serious delays in many areas of Africa's largest country. REUTERS/Zohra Bensemra (SUDAN - Tags: POLITICS ELECTIONS)