The Republic of Congo votes in presidential elections on Sunday with incumbent Denis Sassou Nguesso aiming to extend his decades-long hold on power in the Central African state.

Sassou Nguesso has accumulated 36 years in office — he was most recently re-elected in 2016, after which the opposition was effectively sidelined and his two main rivals sentenced to 20 years’ forced labour.

The 77-year-old retired general appears favoured to win a fourth term in Sunday’s ballot. The largest opposition group, the Pan-African Union for Social Democracy, is already boycotting the ballot.

Sassou Nguesso hopes for a first-round victory over six challengers, including former minister Guy-Brice Parfait Kolelas who was runner-up in 2016.