President Joyce Banda of Malawi has declared this week's election to be "null and void", in a decision that triggered protests from her rival and was challenged by the national electoral authority.
Banda on Saturday claimed there were "serious irregularities" with the poll including multiple voting, ballot-tampering and a malfunctioning computerised vote-counting system.
"I am nullifying the elections, using the powers invested in me by the Malawi constitution," she said. A fresh election would be held within 90 days, she said, adding that she would not stand in the re-run.
I have never heard anywhere in the world where an opposition can rig an election.
The head of the electoral authority said Banda did not have the authority to annul an election, and that vote counting was continuing.
"As far as I know, the president doesn't have any constitutional powers to nullify the election, only the electoral commission has the powers to do so," the commission chairman Maxon Mbendera told Reuters news agency.
The commission had earlier released preliminary results showing opposition Democratic Progressive Party candidate Peter Mutharika leading with 42 percent of the vote, followed by Banda with 23 percent. This was based on 30 percent of the total votes counted.
"Nothing in the constitution gives the president powers to cancel an election," said Mutharika. "I have never heard anywhere in the world where an opposition can rig an election," he said.
Lameck Masina, a journalist based in Malawi, told Al Jazeera that Banda’s move was surprising, but showed the leader had not performed as well as she had expected.
“The president has done this to show that she is still relevant to Malawians, although she is losing miserably at the polls she had a hope to win comprehensively.”
On Friday, the Malawi's electoral commission said it had received 135 complaints of irregularities, which it was investigating before announcing the official results.
"We're committed to a process that's accurate and transparent. As far as we know, polling was free and fair in 99 percent of the centres and both local and international observers have commended the process," said Mbendera.