KINSHASA (Reuters) – 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 destabilised the entire central part of the continent.

Lawmaker Muhindo Nzangi Butondo, a coordinator for opposition presidential candidate Martin Fayulu, called for street protests in Beni, Butembo and nearby Goma on Thursday, describing the CENI’s actions as an attack on the Nande ethnic group.

“(President Joseph) Kabila is taking revenge against the Nandes,” Nzangi said in a statement.

The cities are in a part of the country where conflicts over the past two decades fought at least in part on ethnic grounds have killed and displaced millions.

Government spokesman Lambert Mende declined to respond directly to Nzangi’s comments. He said he understood the anger of those affected but justified the CENI’s decision for security reasons.

Moise Katumbi, a prominent opposition leader who was barred from standing in the election, tweeted that the Congolese “must take matters into their own hands and chase away this regime”

He and Nzangi accused the CENI of trying to tip the election in favour of Kabila’s preferred candidate, Emmanuel Ramazani Shadary.

Opinion polls are rare in DRC, but a survey from a New York-based research group in October showed another leading opposition candidate, Felix Tshisekedi, on 36 percent, followed by Shadary on 16 percent and Fayulu on 8 percent.

Tshisekedi will participate in Sunday’s vote despite the CENI’s announcement, a spokesman for his UDPS party, Paul Tshilumbu, told Reuters.

POSTPONED

The elections – also incorporating legislative and provincial polls – were originally meant to take place in 2016. They have been repeatedly postponed since, sparking violence in which security forces have killed dozens of people.

The CENI pushed the election date back by seven more days last week due to delays in deploying voting materials.

Explaining the three exclusions, it said on Wednesday: “Elections lead to important movements of voters toward polling places, thus … raising the risk of propagation of this disease (Ebola) and providing the conditions for terrorist attacks.”

On Dec 5, Health Minister Oly Ilunga said the Ebola outbreak – declared in August and the second-worst in history – would not interfere with elections, noting that voter registration elsewhere in Congo last year had not been interrupted by a separate outbreak.

A health ministry spokeswoman was not immediately available for comment on Wednesday.

Legislative and provincial elections will take place in Beni, Butembo and Yumbi in March, the CENI said. “We know it’s tough but that’s the situation we are facing,” CENI spokesman Jean-Pierre Kalamba told reporters.

The three cities, home to more than 1.2 million of Congo’s roughly 40 million registered voters, are known as bastions of opposition to Kabila.

Voting elsewhere in the vast central African nation will go ahead on Sunday as planned, the CENI said. Final presidential results would be announced on Jan. 15 and the new president sworn in on Jan. 18.

Kabila, 47, has governed since his father’s assassination in 2001. He won elections in 2006 and 2011, although the latter was marred by widespread accusations of fraud.

Additional reporting by Stanis Bujakera and Fiston Mahamba; Writing by Aaron Ross; Editing by John Stonestreet