YAOUNDE, Cameroon -- YAOUNDE, Cameroon (AP) -- 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.

Analysts have predicted a victory for Biya as the opposition remained divided and his strongest rival was barred from running in August. Eleven opposition candidates were on the ballot.

Following the election, pockets of protests broke out in several cities over the allegations of election fraud.

Tchiroma alleged last week that there were signs of vote tampering, echoing civil society groups' earlier reports of "several irregularities," including attempted ballot stuffing.

The National Episcopal Conference of Cameroon, which monitored the election, said on Monday that the election was marked by a number of irregularities, including relocation of certain polling stations and failure to update the electoral register, which still contained the names of deceased persons. A group of eight civil society organizations that monitored the election also noted the unequal distribution of ballot papers in some polling stations and attempts at ballot box stuffing in their report.

On Sunday, Tchiroma started publishing on his Facebook page results from 18 administrative units which he claims constitute 80% of the electorate, allegedly confirming his victory. His Facebook posts have received praise from his supporters and mockery from critics and regime allies -- including ministers -- who question their authenticity.

Tchiroma, who is in his late 70s, was a government spokesperson and employment minister under Biya but quit the government earlier this year to launch his presidential run. His campaign drew large crowds and backing from a coalition of opposition parties and civic groups.

Biya has been in power since 1982, nearly half his lifetime, making him Cameroon's second president since independence from France in 1960.

During Biya's decades in power, the Central African nation of nearly 30 million people has struggled with challenges from a deadly secessionist movement in the west and chronic corruption that has stifled development despite rich natural resources like oil and minerals. ___

Cameroon arrests at least 20 protesters as tensions escalate after presidential election