BRAZZAVILLE — A leading opposition candidate in the Republic of Congo's presidential election held on Sunday has died from coronavirus-related complications, party officials said on Monday, according to local media reports.

Guy Brice Parfait Kolelas, 61, had been seen in a video shared on social media hours before the poll, receiving oxygen treatment at an undisclosed medical facility.

"I am fighting death," the top presidential candidate, who briefly took off his oxygen mask, was heard saying in French in footage that went viral over the weekend.

He urged his supporters to head to the polls and "vote for change. I will not have fought for nothing. Fight for it," he said.

Election results are expected in several days' time.

Kolelas, a former government minister and one of the main contenders in Sunday's poll, had hoped to topple the reign of 77-year-old President Denis Sassou Nguesso, who has led the country for decades.

Kolelas was a runner-up to Nguesso in the 2016 presidential election, where he amassed about 15 percent of the total ballot.

President Nguesso, who is looking to extend his 36-year reign is expected to cruise to victory ahead of Kolelas and five other presidential contenders as vote counting continues in the oil-rich Central African country.

More than half of the country's five million people registered to vote in the poll, officials said.

The election has been beset with problems, including an internet blackout and independent observers prevented from monitoring the poll and there are concerns that it may not be free and fair.

Under the Nguesso regime, poverty and corruption have remained rife in the Republic of Congo, which ranks among the top 10 oil-producing nations in Africa.

Nguesso emerged as Congo's leader in 1979 but lost his reelection bid in 1992 after the multi-party system was introduced in the country.

He reclaimed power in 1997 and has led the country ever since.

Nguesso amended Congo's constitution in 2015, abolishing laws prescribing a two-term limit for presidents and a maximum age limit of 70 years. — Courtesy CNN