Hundreds of South Africans gather outside Nelson Mandela's home to pay their respects

Hundreds of South Africans have gathered at Nelson Mandela's home in Houghton, a suburb of Johannesburg, to pay their respects to the former president and their affectionate leader "Madiba".

The mood is sombre but also celebratory as the crowds sing freedom songs and the national anthem. Others, many of whom are in their pyjamas, are laying down flowers near the property while others light candles and clutch pictures of the struggle icon, SAnews.gov.za reported early Friday.

There is a high police presence while the roads leading to Mandela's home have been blocked off.

President Jacob Zuma announced the death of Madiba just before midnight in a televised address to the nation. He said Madiba had died peacefully at 8.50 p.m.

Meanwhile, tributes are pouring in from all corners of the world.

British Prime Minister David Cameron said Madiba was a towering figure in our time, a legend in life and now in death - a true global hero. "Across the country he loved, they will be mourning a man who was the embodiment of grace. Meeting him was one of the great honours of my life."

Former US president Bill Clinton tweeted a picture of himself holding hands with Mandela, saying: "I will never forget my friend Madiba."

President of FIFA, world football's governing body, Joseph Sepp Blatter also took to the social network, saying: "My respects to an extraordinary person, probably one of the greatest humanists of our time."

President Zuma has said flags around the country will be flown at half-mast from Friday until the funeral.