Four people were killed in clashes between supporters of a Cameroon opposition leader and security forces who claims to have won recent presidential elections a regional governor said, ahead official results announced Monday.

Issa Tchiroma, who challenged President Paul Biya’s 43-year grip on power in the October 12 vote, had called on his supporters to march peacefully on the eve of the announcement, despite a ban on public gatherings.

Tchiroma says he won 54.8 percent of the vote, but most analysts expect the 92-year-old Biya to win an eighth term in a system his critics say has been increasingly rigged.

In Cameroon’s largest city Douala, the regional governor said demonstrators “attacked” a gendarmerie brigade and police stations in two districts.

“Four people unfortunately lost their lives,” said Samuel Dieudonne Ivaha Diboua, adding that several members of the security forces were also injured.