At least one person has been killed and many others injured in further clashes between supporters of Guinea President Alpha Conde and those of opposition leader Cellou Dalein Diallo.
The West African nation's security minister says the clashes erupted in Kissidougou some 700 km southeast of the capital Conakry after Diallo declared on Monday he had won the October 18 presidential election.
"One person was killed, and many, including police officers who intervened, were injured," Damantang Albert Camara said on Tuesday, adding that a curfew has been declared in the area.
Diallo's victory claim before the official count was completed by the electoral commission raised concerns it could escalate violence in the tense aftermath of the vote.
The decision by 82-year-old Conde to seek a third mandate after he pushed through a constitutional referendum that reset the clock on a term-limit triggered violent unrest over the past year in which at least 50 people were killed in the bauxite-rich West African nation, according to rights groups.
The Economic Community of West African States, the African Union and the United Nations condemned Diallo's claim in a joint statement late on Monday, calling it "regrettable".
Following his announcement, Diallo's supporters swept into the streets in his strongholds, celebrating their alleged victory.
This led to clashes with security forces in which three people were killed, Diallo said.
The electoral commission is expected to start announcing some results on Wednesday or early on Thursday.
Australian Associated Press