Cameroon's security forces fired tear gas on Tuesday to disperse opposition party supporters protesting in the capital Yaounde and the northern city of Garoua, as tensions rise over the outcome of the October 12 presidential election.

Partial results reported by local media, citing the election vote tallying commission, indicate that 92-year-old President Paul Biya is poised to secure an eighth term in office.

Biya, who has ruled the oil- and cocoa-producing Central African nation since 1982, could extend his presidency until he is nearly 100 years old if the constitutional council confirms the results later this week.

Biya's anticipated victory may escalate tensions after his main challenger, Issa Tchiroma, a former minister and ally, claimed victory last week and warned that any other outcome could plunge the country into unrest.

Sporadic protests have erupted nationwide following unverified tallies circulating on social media suggesting Biya's reelection.

Demonstrators in Garoua, Tchiroma's hometown, as well as other cities including Bafoussam, Dschang, Kousserie, and Douala, have voiced concerns over alleged irregularities in the vote count, reflecting broader fears about transparency and fairness in the electoral process.

The government has rejected concerns over alleged irregularities and called for calm until the results are announced.

Cameroon's Interior Minister Paul Atanga Nji said on Tuesday that authorities had arrested more than 20 people in Garoua during street demonstrations.

In a statement, Nji said some of those detained face charges of "incitement to rebellion and insurrection" and will be tried by military tribunal, signalling a government crackdown on dissent amid heightened tensions.