At least 20 people have been arrested in Cameroon in connection with protests over the Oct. 12 presidential election, authorities said on Tuesday, as tensions mounted ahead of the proclamation of results expected later this week.

Cameroon’s Minister of Territorial Administration, Paul Atanga Nji, confirmed the arrest of some of the protesters in the northern city of Garoua in a statement on Tuesday, without stating when and how many were arrested. Twenty of the “several” arrested will be brought before military courts to answer for the charges of insurrection and incitement to rebellion, the statement said, while others involved in criminal acts have been taken to Yaounde for further investigations.

“The government watches with concern acts of provocation and disorder carried out by some trouble makers,” he said, claiming that those arrested were being manipulated by some political actors.

Opposition candidate Issa Tchiroma Bakary claimed victory last week and urged President Paul Biya, the world’s oldest president at 92, to concede. Biya’s party has rejected Tchiroma’s claim of victory and accused the opposition candidate of trying to disrupt the electoral process. The constitutional council is expected to announce the final official results by Oct. 26.