BLANTYRE, Malawi (AP) — Voters in Malawi will return to the polls Tuesday to elect a president after the courts nullified the results of the election held more than a year ago.

The Constitutional Court on Feb. 3 ordered that the election be held again, ruling that the first results were not valid because of widespread evidence of irregularities and vote tampering in the polls held in May 2019.

The court struck down the victory of incumbent President Peter Mutharika citing evidence of voting fraud, including thousands of ballots that appeared to have been altered using typing correction fluid. The ruling was upheld by the Malawi Supreme Court.

Some 6.8 million Malawians are eligible to cast ballots at more than 5,000 polling stations across the country.

U.N. Secretary-General Antonio Guterres called on “all political actors and stakeholders to renew their commitment to credible and peaceful elections, while observing all preventive measures against the spread of COVID-19," the U.N. spokesman said.

“The secretary-general underlines the importance of refraining from violence and hate speech, and of upholding human rights and fundamental freedoms," spokesman Stephane Dujarric said.

In the 2019 polls, seven presidential candidates contested but now the number has come down to two.

The 79-year-old Mutharika, looking for a second and final five-year term in office is up against the leader of the opposition Malawi Congress Party, Lazarus Chakwera, 65. Incumbent Vice President Saulos Chilima was also expected to run, but he decided instead stand as Chakwera's vice-president, in a bid to maximize chances of unseating Mutharika.

The contest appears to be very close. The Chakwera/Chilima ticket may win 51% of the vote, according to a poll in early June by Malawi's Institute of Public Opinion and Research.

A number of local and international organizations will observe the new elections, in an effort to make sure that they are free and fair, the newly-elected chairman of the Malawi Electoral Commission Chifundo Kachale said.

The European Union, African Union, Southern African Development Community, diplomatic missions and the Commonwealth will be observing the elections, the electoral commission's spokesman Sangwani Mwafulirwa told AP.

Britain will also be observing the elections, the U.K.'s Acting High Commissioner to Malawi David Beer confirmed. He said that the U.K., the U.S. and the European Union are also funding domestic observation to be carried out by Malawian non-governmental organizations.