YAOUNDE, Cameroon (AP) — Cameroon ’s electoral commission on Saturday rejected the candidacy of Maurice Kamto in the upcoming presidential election, fueling fears of unrest and increasing the likelihood of another Biya victory.

Kamto, a former government minister, is seen as the main challenger to long-serving President Paul Biya.

The electoral commission, ELECAM, said it approved 13 presidential candidates, excluding Kamto. No reason was given. Biya is included.

Kamto, who has two days to appeal, was considered Biya’s strongest rival in past elections. He came second during the last presidential election in 2018 with 14% of the vote, while Biya cruised to victory with over 70% in an election marred by irregularities and a low turnout.

Biya, 92, the world’s oldest serving head of state, said last month he would seek reelection on Oct. 12 despite rumors that his health is failing. He has been in power since 1982, nearly half his lifetime.

Biya’s rule has left a lasting impact on Cameroon. His government has faced various challenges, including allegations of corruption and a deadly secessionist conflict in the nation’s English-speaking provinces that has forced thousands out of school.

Fears of protests and unrest surged around Saturday’s release of the list of approved candidates.

Security forces were deployed around the ELECAM headquarters and along major roads in Yaoundé, the capital, and in Douala, the economic hub.

The United Nations Department of Safety and Security had warned Friday that the announcement could trigger protests in the capital.