Malawi’s president Peter Mutharika says he will contest a court ruling that overturned his election last May.
Mr Mutharika, Malawi’s president since 2014, won the election with a 38.5% share of the vote. Opposition party leader Lazarus Chakwera came second with 35.41%
On Monday, judges annulled the vote citing irregularities and ordered a new election within 150 days.
There have been regular anti-government protests since the election.
Mr Mutharika said he will lodge an appeal against the ruling by five judges.
This was the first time a court had annulled an election in Malawi, creating further uncertainty in the southern African state.
Presidential spokesman Mgeme Kalirani said the ruling “cannot be allowed to stand … it will create a lot of problems in the country’s jurisprudence.
“It is a great miscarriage of justice,” he added in a statement.
On Tuesday, Mr Chakwera told tens of thousands of his supporters that the ruling was a victory for democracy.
“It is Malawi that has won. It is Africa that has won,” he added.
Lawyers for Mr Chakwera and Saulos Chilima, another losing candidate, said correction fluid – known by the brand name Tipp-Ex – had been used on some of the tallying forms sent in by polling stations.
The changes were made after they had been signed by party agents, they said.
The lawyers also said that in some cases polling officials sent in the wrong copy of the results sheet to the main tallying centre.
They also found some mathematical errors in a small number of cases.
Though in each case there were not a huge number of errors, the lawyers said that the evidence pointed to a flawed process.
Since the disputed results were announced last May, there have been regular anti-government protests. Some of these have resulted in looting and the destruction of property, including government offices.
Two people – one police officer and one civilian – are known to have been killed during the demonstrations.