Cameroonian opposition leader Maurice Kamto is challenging his disqualification from October’s presidential election, filing an appeal on Monday with the country’s Constitutional Council.

Last week, Kamto, who was runner up to incumbent Paul Biya in 2018, was barred from this year’s election by Cameroon’s electoral oversight body Elecam. Elecam cited the fact that Manidem, the party Kamto represents, had already submitted a candidate for the 2025 vote.

Kamto’s supporters however are crying foul, pointing out that other parties are also running multiple candidates, without push-back from Elecam.

Kamto is widely seen as the main challenger to 92-year-old President Biya, the world’s oldest serving head of state who has ruled Cameroon since 1982.

The United Nations Department of Safety and Security has warned that the exclusion of candidates could lead to public protests in the capital Yaoundé.