Malawi’s president is planning to contest a court decision overturning his election in May last year.
A spokesman for Peter Mutharika said he would lodge an appeal with the Constitutional Court.
On Monday judges annulled the vote, citing widespread irregularities. They ordered a new election within 150 days.
Malawi’s governing Democratic Progressive Party has urged its supporters to remain peaceful.
The opposition leader, Lazarus Chakwera, told thousands of celebrating supporters that the verdict was a victory for democracy.
He came a close second to Mr Mutharika, and went to court alleging fraud.
President Peter Mutharika won a second term in May with 38.6% of the vote.
But opposition candidates Lazarus Chakwera, who came second, and Saulos Chilima, who finished third, went to court to argue that the election was not fair.
They said the way the election was conducted was full of irregularities.
The judges, who arrived in court in the capital, Lilongwe, under military escort, upheld the complaint on Monday.
According to the official results, Mr Chakwera, who claims he won the election, garnered 35.4% of the vote as the flag bearer for the Malawi Congress Party.
Mr Chilima, a former ally of the president, got 20.2%. He was the candidate for the UTM.
There is a high level of anxiety in the country following months of tense clashes between the police and opposition supporters.
