Mozambique's main opposition leader, Venancio Mondlan, has announced that he will run for president on January 15 after rejecting his defeat in the presidential election.
His announcement came as his supporters staged violent protests across the country to demand an end to the 49-year rule of the Frelimo party.
The capital, Maputo, was like a ghost town on Christmas Eve, with almost all businesses closed and people staying at home to avoid the city's biggest riots since Frelimo came to power at independence in 1975.
Frelimo offices, police stations, banks and factories were looted, vandalized and burned across the country.
The latest unrest began on Monday after Mozambique's highest court upheld the victory of Frelimo's presidential candidate, Daniel Chapo, in elections held in October.
Mondlane disputed the result, claiming the poll was rigged.
In a Facebook Live broadcast to his supporters on Tuesday, Mondlin said he rejected the constitutional court's decision, adding that he would take over as president on January 15, the day Chapo is due to be sworn in.
President Filipe Nyusi is due to step down at the end of his two terms.
It is unclear how Mondlan intends to take over as he is currently in self-imposed exile in an unknown country.
He often rallies his supporters through Facebook Live speeches, but has urged them to remain peaceful.
“We stand with the people. We do not advocate any form of violence,” Mondlein said in his latest address.
Chapo has yet to comment on his statement.
The October election was the first time both men ran for president, with the electoral commission declaring Chapo the winner with 71% of the vote to Mondlan's 20%.
The Constitutional Court reviewed the result, giving the Frelimo candidate 65% and Mondlan 24%.
Human rights groups say more than 100 people have been killed in post-election riots.
They blame security forces for many of the killings, but police commander Bernadino Raphael previously told the BBC that his officers were defending themselves after being attacked.
Mondlan fled Mozambique after accusing the police of threatening behaviour, and two of his aides were shot dead in October.
The 50-year-old evangelical pastor ran in the election as an independent candidate after breaking away from the main opposition Renamo party.
His support is strongest among young people, many of whom are unemployed and demanding change.
Frelimo nominated 47-year-old Chapo as its youngest presidential candidate.
He earlier dismissed suggestions that he and Frelimo rigged the poll, saying: “We are an organized party that prepares its victories.”