This is after rejecting his defeat in presidential elections.
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 shut and people staying at home to avoid being caught up in the worst unrest in the city since Frelimo rose to power at independence in 1975.
Frelimo’s offices, police stations, banks and factories have been looted, vandalised and set ablaze around the country. Since Monday, at least 21 people have been killed in the unrest, the interior minister said late on Tuesday.
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 had challenged the result, alleging that the poll was rigged.
In a Facebook live broadcast to his supporters on Tuesday, Mondlane said he rejected the ruling of the constitutional court, adding that he would assume the office of president on 15 January – the day that Chapo is due to be sworn in. (BBC News)
Oh there is such a thing like installing one self as President.