The United Nations and key organizations in Europe, Africa and the French-speaking world have issued a rare joint statement highlighting growing concern at rising political tensions in Congo ahead of elections where some fear President Joseph Kabila may try to stay in power despite being constitutionally barred from a new term.

The U.N., European Union, African Union and International Organzation of La Francophonie underlined "the crucial importance of holding a successful political dialogue" with all Congolese parties that leads to a consensus on holding free, transparent and credible elections.

Kabila has yet to comment publicly on his political future. Congo's top opposition presidential candidate, Moise Katumbi, flew to South Africa for medical treatment on May 20 after authorities issued a warrant for his arrest.