Nigerian President Muhammadu Buhari's chief of staff has died after contracting the novel coronavirus, the presidency said on Saturday.

Buhari's office announced in a statement that it "regrets to announce the passage" of Abba Kyari, who acted as gatekeeper to the president of Africa's most populous nation.

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"The deceased had tested positive to the ravaging COVID-19, and had been receiving treatment. But he died on Friday, April 17, 2020," the statement said.

"May God accept his soul."

Kyari, in his 70s, was the highest-profile COVID-19 death in the West African country, which has 493 confirmed cases and 17 deaths, according to the Nigeria Centre for Disease Control.

Influential technocrat

The influential technocrat, who was reported to have suffered from underlying health issues, was seen as one of the dominant figures in the tight-knit group of advisers around Buhari.

He reportedly controlled access to the president, a 77-year old former military ruler now in his second term as democratically elected leader, overseeing key meetings and granting audiences.

Kyari tested positive for coronavirus in late March after visiting Germany, forcing a string of top Nigerian officials who had been in contact with him to self-quarantine.

In a statement released on March 29, Kyari said he had been transferred to Lagos, Nigeria's biggest city, for private medical treatment and hoped "to be back at my desk very soon".

There has been no official confirmation on whether Buhari has taken a test, but the president has since made repeated televised speeches imposing restrictions to curb the spread the virus.

The central government has imposed a lockdown on Nigeria's economic hub Lagos and capital Abuja, while state governors have ordered a number of measures in other regions.

Economic consequences

The extension of the lockdown is expected to add to the hardship of millions of Nigerians living hand-to-mouth, often on less than one dollar a day.

Buhari said on Monday he was "fully aware of the great difficulties experienced especially by those who earn a daily wage".

"But despite these realities, we must not change the restrictions," he added.

The government has pledged a series of support measures to ease the financial pain for the most vulnerable, but there have been widespread complaints that not enough is being done for those facing hunger.

"The vast majority of Nigerians depend on daily wages, they have to go out to get money and buy food to put it on the table for their families," Al Jazeera's Ahmed Idris, reporting from the capital, Abuja, said.

"For the next two weeks, they are going to stay at home with no work and no chance of getting money."

Experts say the country of 200 million is highly vulnerable to the spread of the disease given its weak healthcare system and high population density.

The Africa Centers for Disease Control and Prevention said Saturday that Africa has now more than 1,000 deaths from COVID-19

A total of 52 of the continent’s 54 countries have reported the coronavirus, with the overall number of cases more than 19,800.

The World Health Organization on Friday noted a 51% increase in cases in Africa and a 60% jump in deaths in the past week. But the WHO chief warned that because of a shortage of testing “it’s likely the real numbers are higher than reported.”

The Africa CDC has said more than 1 million test kits will be rolled out starting next week.