President Muhammadu Buhari missed his weekly cabinet meeting for the third straight time Wednesday as concerns mounted about his health, while his wife took to Twitter to defend him.

President Muhammadu Buhari disappeared for six weeks of medical leave in London earlier this year, leading some to call for his replacement. The 74-year-old returned to work in mid-March but often works from home, according to aides.

The uncertainty over Buhari's health has raised fears of instability in Africa's most populous nation and one of its top oil producers.

A tweet from his office on Wednesday said the latest cabinet meeting was being presided over by the vice president, Yemi Osinbajo, who had been in charge during the president's medical leave.

Buhari's office last month put out a statement saying he remained in charge even though doctors had advised "on his taking things slowly." 

On his return to Nigeria in March, he made reference to blood transfusions and said he had not been so sick in decades.

Buhari's wife, Aisha, tweeted late Tuesday that her husband's health "is not as bad as it's being perceived."

Nigeria continues to grapple with crises that include Boko Haram extremist attacks, millions facing starvation in the country's northeast and an economy that last year contracted for the first time in a quarter-century.

AP