Supporters of Angola's main opposition UNITA party stand on a lamppost as they wave flags during an election rally in Luanda August 25, 2012. Angola's main opposition called on Friday for the August 31 national election to be postponed for a month to allow time to correct a lack of transparency in the poll and violations of the electoral law. Campaigning for the election, only the second in Africa's No. 2 oil producer since the 27-year civil war ended a decade ago, has been marked by wrangling over transparency. Voters will elect a parliament and the leader of the biggest party will then become president. REUTERS/Siphiwe Sibeko (ANGOLA - Tags: POLITICS ELECTIONS)