Equatorial Guinea’s President and Africa’s longest-serving leader, Teodoro Obiang Nguema Mbasogo, is expected to win another seven-year term in elections Sunday. Obiang came to power in the former Spanish colony in 1979 after organizing a coup against his uncle Macias Nguema.

Obiang, 73, is expected to win the mandate with a customary majority of at least 90 percent.

“Whoever does not vote for me is rejecting peace and opting for disorder,” Obiang told a crowd at Malabo Stadium during a campaign rally, according to reports. The incumbent, who captured more than 95 percent of the votes in the last election in 2009, faces six mostly unknown opponents on Sunday.

The country's opposition leaders and international civil society groups have already dismissed Sunday's vote as "not credible," according to reports.

The small African nation with few resources came to prominence after the discovery of offshore oil in the early 1990s. With investments from U.S. oil companies, the country made gains and now has the highest per capita gross domestic product of any African country — about $37,000 — according to the U.N.'s 2014 Human Development Report.

However, as it is ranked 144 out of 187 countries in the Human Development Index, Equatorial Guinea has by far the world’s largest gap of all countries between its per capita wealth and its human development score, Al Jazeera reported.

The elections have no chance of being free and fair, Severo Moto, the exiled leader of the main opposition Progressive Party of Equatorial Guinea, told Bloomberg.

The government has denied allegations made by the opposition and international rights groups about human rights abuses and corruption.

“Political stability is essential for the country and the incumbent president is the person to provide it for the next seven years,” Energy Minister Gabriel Mbaga Obiang Lima, one of Obiang’s sons, reportedly said.