Opposition leaders have alleged that the election was rigged by altering results sheets using correction fluid.

Malawi’s constitutional court has begun hearing an opposition application to overturn the results of the country’s presidential election held nearly three months ago.

The hearing on Thursday in the capital, Lilongwe, came after the main opposition Malawi Congress Party (MCP) and the United Transformation Movement (UTM) lodged complaints of alleged fraud in the May 21 vote.

President Peter Mutharika, leader of the ruling Democratic Progressive Party, was re-elected after narrowly defeating Lazarus Chakwera of the MCP.

Chakwera alleges he is the rightful winner of the election, calling the result that saw him losing by 159,000 votes as “daylight robbery”.

The opposition has claimed that results sheets were altered using typewriter correction fluid.

Mutharika has dismissed the doubts over him winning 38.57 percent of the vote, saying international observers had deemed the polls “peaceful, free and fair.”

On Thursday, UTM leader and former Vice President Saulos Chilima was the first to take the witness stand, after the defence failed in its attempts to force a postponement of the hearing.

The attorney general had asked for a three-day extension, which opposition lawyers opposed outright, claiming that the case had already suffered delays – and that it was imperative that the hearing be completed in a timely fashion as required by law.

The judges said the case will take a maximum of 12 days to complete, and will conclude no later than August 20.

The case has gripped Malawians, with many on Thursday glued to their phones as they listened intently the radio broadcasting of the court proceedings – on the streets, in the workplace, and near the court premises.

Security forces were deployed near the court, where a small crowd of opposition supporters also gathers.

When the court met last month for preliminary hearings, police used tear gas to disperse opposition supporters assembled outside.

On Tuesday, a peaceful demonstration in Lilongwe calling for electoral accountability later turned violent as protesters and the police clashed, with the latter once again using tear gas to disperse the crowd.

Several shops were looted and cars were torched, including an armoured police vehicle.

Kandani Ngwira in Lilongwe contributed to this report