The opposition in the West African state of Guinea vowed Monday to boycott legislative elections set for February 16 and "prevent" them from taking place, in a dispute focussed on the country's electoral roll.
"We have decided we cannot take part," opposition chief Cellou Dalein Diallo said after meeting with the heads of around 20 opposition groups.
"It's not just a question of boycotting the elections and standing idly by. We will prevent these elections from taking place," he said.
Diallo charged that there had been "massive inclusion of minors" on the electoral lists, while people who had the right to vote had been blocked.
"We cannot accept having an election based on this electoral roll," Diallo said.
Fellow opposition leader Etienne Soropogui, said: "We took an important decision today, which consists of no longer (running against President) Alpha Conde so long as we do not have the conditions for free and transparent elections."
Guinea has been wracked by rolling demonstrations sparked by concerns that Conde, 81, plans to stay in office beyond the two legally mandated two terms.
Conde has not yet confirmed whether he plans to run again.
But his announcement last week of a new draft constitution sparked a fresh wave of accusations that he was scheming to extend his rule.
A nationwide protest is set for Friday.
About 20 people have died since the protests began in mid-October, according to an AFP tally, and one gendarme has also been killed.
Hundreds of people have been arrested. Civil rights campaigners say the police have used excessive force and carried out arbitrary arrests.
Guinea is one of the world's poorest countries, despite owning huge mineral resources.
Conde, who was jailed and spent time in exile under Guinea's previous authoritarian regimes, became the country's first democratically elected president in 2010.
He was re-elected in 2015.
Despite initial hopes of a new political dawn in the country, critics say his rule has become increasingly authoritarian.