The Republic of Congo voted in elections on Sunday with President Denis Sassou Nguesso expected to extend his decades-long rule even as the Central African nation faces its worst economic crisis since the slump in global oil prices in 2014.

The 77-year-old incumbent is seeking a fourth five-year term and faces six opposition candidates. Catholic Church leaders and advocacy groups have expressed concern that the conditions for a credible vote aren’t in place. Human rights group Amnesty International has criticized his administration for arresting and jailing opponents, while local civil-society organizations estimate dozens of political prisoners have been jailed.

Among Sassou Nguesso’s main challengers are ex-finance minister Mathias Dzon; retired army Colonel Albert Oniangue, who is now a pastor in an evangelical church; and former Civil Service Minister Guy Brice Parfait Kolelas, who was runner-up in 2016.

Kolelas, 61, was hospitalized with Covid-19 and set to be evacuated on a government-chartered plane on Sunday. The leader of the Union of Humanist Democrats is Sassou Nguesso’s main challenger, according to polls. If no candidate gets more than 50% of the vote the two top candidates go to a runoff.

Internet was cut from midnight on Saturday, according to observatory Net blocks. The shutdown follows a pattern of similar information blackouts imposed by authorities during 2016 presidential elections, the organization said in a statement on its website Sunday.

That poll was followed by protests as Sassou Nguesso was declared the winner. Tens of thousands were displaced in the post-election conflict, according to the United Nations. After a presidential campaign without major incidents, Sunday’s vote is expected to be largely peaceful.

Interior Minister Raymond Zephyrin Mboulou charged with organizing the election said on Saturday “each vote cast in favor of a candidate will be counted in favor of this candidate.” Two and a half million voters have registered for the poll.