Voters in three Congolese cities known as anti-government strongholds will be excluded from Sunday's presidential elections on security and health grounds, officials said, prompting calls for protests from angry opposition leaders.

Electoral commission CENI said an Ebola outbreak was behind the cancellation of the ballot in the eastern Democratic Republic of Congo cities of Beni and Butembo. It cited ethnic violence for the same action in the western city of Yumbi.

The election is meant to lead to the first democratic transfer of power in Africa's leading copper producer, where conflicts have in the past destabilized the entire central part of the continent.