Cape Town

Video footage showed a plume of black smoke filling the sky, with huge flames coming out from the roof of the building.

President Cyril Ramaphosa visited the scene and called it a "terrible and devastating event".

A 51-year-old man was being held and questioned by the authorities, police said.

The blaze, which began shortly after 6am local time came the day after Archbishop Desmond Tutu's state funeral at St George's Cathedral, near Parliament.

Swiss great Federer will face off against his most famous rival in the sixth edition of the Match for Africa series, organised by the 20-time grand slam winner's foundation.

Federer will team up with Microsoft owner Bill Gates to face Nadal and Daily Show host Trevor Noah, who was born in South Africa, for a doubles encounter before the two tennis greats meet in a singles match.

When planning to host the event in Cape Town, Federer only had one opponent in mind and said he had been trying to enlist Nadal's help for some time.

The Blitzboks, England and USA all progress to the Cup quarter-finals unbeaten after taking three wins from three in the pool stages. South Africa face Fiji in the final eight, reigning Cape Town champions England play New Zealand, Canada face France and USA play Argentina. 

South Africa are targeting their second tournament win in as many weeks after taking glory in the opening round of the 2018 world series in Dubai last weekend. 

Tutu, 83, was admitted to a Cape Town hospital on Tuesday, where he is receiving an "intensive course" of antibiotics to fight a "stubborn infection," the Desmond and Leah Tutu Legacy Foundation said earlier in a statement.

"We are confident that he will recover well from the treatment," Tutu's daughter Mpho said in a televised press briefing.

Tutu, 83, was admitted to the hospital on Tuesday. At that time, his daughter, Mpho, said their family hoped the Nobel Peace Prize laureate would be able to return home in a "day or two."

 A foundation named after Tutu and his wife Leah said Wednesday that the retired archbishop wants to thank people who have sent love and prayers by telephone, social media and other means.

Tutu has been treated for prostate cancer for many years.