What you need to know:
- President Denis Sassou Nguesso, 77, has held office for a total of 36 years, making him one of the longest-serving leaders in the world and head of a deeply poor nation.
The Republic of Congo's main opposition party will boycott the March 21 elections in which President Denis Sassou Nguesso, in power for decades, is running for re-election.
The 77-year-old has held office for a total of 36 years, making him one of the longest-serving leaders in the world and head of a deeply poor nation.
The holding of the presidential election "must not divide us as it has done in the past", said Pascal Tsaty Mabiala, first secretary of the opposition group Pan-African Union for Social Democracy (UPADS).
"We have unanimously decided not to take part in it, either directly, or by a proxy candidate," he added.
UPADS - the group of former president Pascal Lissouba, who died in France last August - is the only opposition party to have a parliamentary group in the current national assembly.
Lissouba was overthrown in a brief civil war in 1997 by Sassou Nguesso, who had lost the country's first multi-party elections in 1992.
In 2015, the country staged a referendum on removing a 70-year age limit and a ban on presidents serving more than two terms.
The move paved the way for Sassou Nguesso to secure a third term in 2016 elections that were marred by bloodshed and claims of fraud.
His rivals, former general Jean-Marie Michel Mokoko and ex-minister Andre Okombi Salissa, disputed the results.
They were arrested, put on trial and each handed 20 years in jail on charges of undermining state security.
The country is in the grip of a deep economic crisis, triggered by the slump in oil prices but worsened by long-standing debt and the impact of the coronavirus pandemic.