Nigeria's Aliko Dangote has been listed by Forbes magazine as Africa's richest man for the 13th year in a row despite the country's economic difficulties.

The 20 billionaires on its list are worth a combined $82.4bn (£64.8bn).

"The continent remains one of the world's toughest places to build - and hold on to - a billion-dollar fortune," the business magazine says.

Its list tracks the wealth of African billionaires who reside in Africa or have their primary business there.

Mr Dangote's fortune rose by $400m over the last year to a net worth of $13.9bn, Forbes said.

The 66-year-old businessman made his fortune in cement and sugar - and last year opened an oil refinery in Nigeria's economic hub of Lagos.

Since Bola Tinubu took over as president in May, following disputed elections, the value of the local currency the naira has plummeted and the removal of a fuel subsidy has sent prices sky-rocketing.

Forbes said Mr Dangote retained his top ranking despite the naira's devaluation "that offset the rising share price of Dangote Cement".

South African luxury goods magnate Johann Rupert held on to the number two spot with another South African, former diamond miner Nicky Oppenheimer, in the third spot.

South Africa has another four people on the rich list, followed by Egypt with five, Nigeria with four and Morocco with two. Algeria, Tanzania and Zimbabwe each have one billionaire.