More than 25 million registered voters in the Democratic Republic of Congo are preparing for the nation's first open election in more than 40 years .
Violence marred the last hours before Sunday's election, with rioting in different parts of the country, and shooting incidents between security guards of rival candidates.
Incumbent President Joseph Kabila faces 31 other candidates. There also are more than nine thousand candidates running for 500 legislative seats.
If no single presidential candidate wins 50 percent of the votes, the two front-runners will face each other in a second round scheduled for October. There will only be one round of voting for legislators.
Supporters of the different candidates have suggested they might take up arms if the election does not go their way.
The United Nations has trained 50-thousand election officials to run the voting. The head of the U.N.'s huge peacekeeping mission in the Democratic Republic of Congo says the election will be as free and fair as possible.
The White House issued a statement on Friday supporting the elections and calling on all parties to refrain from violence.