Efforts by Uganda's main opposition parties to back a single candidate in elections next year have collapsed after they failed to reach a unanimous decision.

The coalition of parties, known as The Democratic Alliance, said Thursday that there was no consensus on whether to pick three-time presidential challenger Kizza Besigye or former Prime Minister Amama Mbabazi. The failure to reach a consensus means both politicians are likely to contest the presidency in elections early next year.

Opposition activists believe a united opposition could mimic the success in Nigeria of Muhammadu Buhari, whose coalition defeated an incumbent president in elections.

Francis Mwijukye, an aide to Besigye, said Mbabazi's viability was questioned because he remains a member of the ruling party.