Two opposition parties in Cameroon announced they were joining forces on Friday as part of an effort to defeat current President Paul Biya in this weekend's presidential election.

Akere Muna, the leader of the People's Development Front (FDP), said he decided to "withdraw" his candidacy for this Sunday's vote in order to benefit Maurice Kamto, the head of the Movement for the Rebirth of Cameroon (MRC).

"I firmly believe that the future of Cameroon is the top priority and is worth every personal sacrifice," Muna wrote on Twitter.

Although the parties are hoping to unseat 85-year-old Biya, the new alliance did not include the main opposition Social Democratic Front and its candidate Joshua Osih.

Both Osih and the MRC's Kamto are considered front-runners.

Allegations of election fraud

Earlier Friday, Kamto's MRC alleged that a "massive fraud" was taking place in Cameroon to help Biya secure a seventh term in office.

The MRC alleged that voter registration has continued although the deadline has already passed and that polling cards have been forged.

Cameroon's election authorities have faced accusations of favoring Biya for years. He won the 2011 election with 78 percent of the votes in a poll that was described as "flawed" by election observers as well as opposition politicians.

Biya, who has been in power for 35 years, faces seven opposition candidates in Sunday's vote.

Security is expected to be tight for the vote, while Cameroonian authorities have ordered a ban on rail, road and air travel within the country, according to a decree seen by news agency Agence France-Presse.

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