Malawian President Peter Mutharika has slammed a decision by the Constitutional Court to annul his re-election but promised to run in a fresh ballot ordered by the judges.The southern African nation made history on Monday when the top court ruled in favour of an opposition bid to cancel last May's presidential election results over allegations of fraud.After six months of hearings broadcast on public radio, the judges declared Mutharika was "not duly elected".They cited what they called massive and widespread irregularities, especially the use of correction fluid on ballot sheets, and ordered a fresh poll within 150 days.Parliament on Thursday said it would comply with the court orders and would pass the necessary laws by February 24 to enable the staging of fresh polls. Mutharika, 79, has already vowed to appeal against the annulment to the Supreme Court. He has six weeks in which to submit the challenge.He went on the offensive on Wednesday, blasting the verdict as a "serious subversion of justice" that marked the "death of Malawi's democracy"."We are not appealing to stop the next election," he said during an address to the nation from the capital Lilongwe. "We are ready to campaign and win as we have always done."READ: Malawi’s constitutional court cancels presidential vote resultThe president added that he was appealing to correct "fundamental errors in the judgement" and to "seek justice"."Let us not be carried away by this court ruling because it is not the end of everything," he added.It is the first time a presidential election has been challenged on legal grounds in Malawi since independence from Britain in 1964, and only the second African vote result to be cancelled after the 2017 Kenya presidential vote.Lazarus Chakwera, the leader of the main opposition Malawi Congress Party (MCP), who came a close second to Mutharika, hailed the verdict as a win for democracy."The future is bright," he tweeted late on Wednesday.His party spokesperson scorned Mutharika over his reaction to the court ruling."We are surprised that the president, being a constitutional law professor, has reacted in such a manner," MCP spokesman Eisenhower Mkaka told AFP."We thought that the court was just and fair and the president should have been the first one to appreciate that," he added. Mutharika was declared the winner of the May 21 election with 38.5 percent of the vote, with Chakwera losing by just 159 000 votes.Chakwera said he was robbed of victory and went to court to challenge the result.He was backed in the legal challenge by the former vice president Saulos Chilima, who fell out with Mutharika and contested the election on an opposition ticket.The constitutional court judges concurred that "the irregularities and anomalies have been so widespread, systematic and grave... that the integrity of the results has been seriously compromised."The court said only 23% of the results sheets had been able to be verified, and that the outcome announced by the electoral commission "cannot be trusted as a true reflection of the will of the voters".'Future is bright' Allegations of vote-rigging sparked protests across the normally peaceful country last year shortly after results were announced. Several of the demonstrations turned violent.Mutharika on Wednesday called on all Malawians to "keep calm" adding that the judgement was not the end of "litigation in the May 21 elections case".Mutharika will remain president until the new election, the court ruled, with Chilima as his deputy.Parliament has meantime begun to prepare the legislative changes ordered by the court, including amending the current first-past-the-post electoral system for choosing a president.The court interpreted the constitutional provision of "majority of the electorate" as meaning that a candidate should be chosen by more than 50% of the ballots cast."What parliament is being asked to do is to bring the enabling legislation," parliament speaker Catherine Hara told a news conference in Lilongwe on Thursday.