Issa Tchiroma Bakary – a prominent minister and long-time ally of President Paul Biya – has quit Cameroon’s government, in the hope of ending 92-year-old Biya’s four-decade grip on power in upcoming elections.

Just four months before the central African nation goes to the polls, Bakary says the Biya administration he was part of has “broken” public trust and he is switching to a rival political party.

“A country cannot exist in the service of one man,” Tchiroma said on Wednesday.

His other roles during almost two decades in government include being a spokesman for the Biya government and, until his resignation on Tuesday, he was employment minister.

Paul Biya – the world’s oldest head of state – has yet to confirm if he will stand for president a seventh time.