The leader of Congo's largest opposition party says they would agree to a further delay of elections until June 2018 with assurances that President Joseph Kabila steps down at the end of this year and a new transition government is put in place.

Opposition leader Felix Tshisekedi said Tuesday that the opposition coalition known as the Rassemblement refuses to participate in further dialogue unless it includes discussion of Kabila's exit.

Congo has seen widespread anger over Kabila's stay in power after his mandate ended in December and elections were delayed. The election commission recently said elections cannot take place until 2019, citing deadly violence in the Kasai region.

Ruling party spokesman Andre-Alain Atundu says the election commission is the only body that can determine when elections can be held.