(BSS/AFP) - Four people were killed in clashes between security forces and supporters of a Cameroon opposition leader who claims to have won recent presidential elections, authorities said ahead of the announcement of official results Monday.

Issa Tchiroma, who challenged President Paul Biya`s 43-year grip on power in the October 12 ballot, 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 on Sunday.

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

Protesters at the scene showed AFP journalists bullet casings they said they collected after security forces fired shots near the gendarmerie.

The shooting with "live ammunition" began after a volley of tear gas, a demonstrator told AFP on condition of anonymity.

"They fired, three people, three bodies fell in front of us," he said.

The Constitutional Council is due to announce the final election results at 11:00 am (1000 GMT) Monday in the capital Yaounde.

- `Security crisis` -

Earlier Sunday, police had fired teargas to disperse hundreds of people in Tchiroma`s northern stronghold of Garoua, where activists carried Cameroonian flags and banners reading "Tchiroma 2025" and chanted "Goodbye Paul Biya, Tchiroma is coming".

For several days, dozens of supporters have gathered around the home of the opposition leader, who claimed in a video Sunday that military personnel had tried to take him away.

In Yaounde, the call to protest did not seem to have been followed amid a heavy police presence.

But in Douala, prior to the reported clashes, an AFP journalist observed several dozen people gathered near the airport, defying the ban on demonstrations ordered by the department`s prefect.

On Friday, two opposition figures from a coalition that had endorsed Tchiroma as a candidate were arrested in their homes in Douala, the coalition said.

They are Djeukam Tchameni, president of the Movement for Democracy and Interdependence in Cameroon, and Anicet Ekane, president of the African Movement for the New Independence of Cameroon.

Significant disruptions to internet access have also been reported in recent days, which according to monitor NetBlocks "may limit coverage of events on the ground".

Minister of Territorial Administration Paul Atanga Nji said on Saturday the protests "create the conditions for a security crisis" and contribute to "the implementation of an insurrectionist project".