President John Magufuli of Tanzania, a prominent COVID-19 sceptic in Africa whose populist rule often cast his East African country in a harsh international spotlight, has died. He was 61 years old.

Magufuli’s death was announced on Wednesday by Vice President Samia Suluhu, who said the president died of heart failure.

“Our beloved president passed on at 6 pm this evening,” said Suluhu on national television. “All flags will be flown at half-mast for 14 days. It is sad news. The president has had this illness for the past 10 years.”

The vice president said that Magufuli died at a hospital in Dar es Salaam, the Indian Ocean port that is Tanzania’s largest city.

Although Vice-President Samia Suluhu said the cause of Magufuli’s death was heart failure, Opposition politicians had earlier claimed he’d been diagnosed with COVID-19.

Magufuli had not been seen in public since the end of February and top government officials had denied that he was in ill health even as rumors swirled online that he was sick and possibly incapacitated from illness.

Magufuli was one of Africa’s most prominent deniers of COVID-19. He had said last year that Tanzania had eradicated the disease through three days of national prayer. Tanzania has not reported its COVID-19 tallies of confirmed cases and deaths to African health authorities since April 2020.

But the number of deaths of people experiencing breathing problems reportedly grew and earlier this month the U.S. embassy warned of a significant increase in the number of COVID-19 cases in Tanzania since January. Days later the presidency announced the death of John Kijazi, Magufuli’s chief secretary. Soon after the death was announced of the vice president of the semi-autonomous island region of Zanzibar, whose political party had earlier reported that he had COVID-19.

Critics charged that Magufuli’s dismissal of the threat from COVID-19, as well as his refusal to lock down the country as others in the region had done, may have contributed to many unknown deaths.

It is hard to gauge how most Tanzanians regarded Magufuli’s COVID-19 skepticism, in a country where he remained genuinely popular among many for his seemingly frank talk against corruption even as he curtailed political freedoms and increasingly asserted an authoritarian streak. Police arrested at least one man earlier this week who was accused of spreading false information about Magufuli’s health.

First elected to the presidency in 2015, Magufuli was serving a second five-year term won in 2020 elections that the opposition and some rights groups said were neither free nor fair. His main opponent in that race, Tundu Lissu, had to relocate to Belgium after the vote, fearing for his safety. Lissu, who was among the first to raise questions about the whereabouts of Magufuli after he went missing for several days, had been shot 16 times back in 2017, an attack he blamed on government agents because of his criticism of the president.

Magufuli had become so powerful by the start of the COVID-19 outbreak that he could deny the existence of a pandemic without incurring the criticism of his predecessor and other prominent people within Tanzania. In early 2021, amid speculation that Magufuli would seek an unconstitutional third term when his mandate expired in 2025, his ruling Chama Cha Mapinduzi party was compelled to deny such a thing could happen.

John Pombe Magufuli was born on Oct. 29, 1959, in the rural area of Chato in the country’s northwest. The son of a subsistence farmer, he tended his father’s cattle but was a good student, seeing classroom studies as a way out of poverty. Magufuli earned a bachelor’s degree in mathematics and chemistry at the University of Dar es Salaam in 1988. Much later, in 2009, he earned a doctorate in chemistry from the same university.

For years he was a secondary school teacher and then a chemist with a farmers’ cooperative union before entering politics as a lawmaker representing Chato in the National Assembly. The legislative role was a springboard to a career in national politics, and he served in several Cabinet positions, notably as the hardworking public works minister nicknamed “the bulldozer” in the administration of predecessor Jakaya Kikwete.

A reputation as an incorruptible man was widely seen as one reason for his selection as the new leader of Chama Cha Mapinduzi, the party that had dominated Tanzania since independence but whose popularity was declining in large part because of allegations of rampant corruption.