Former South African president Nelson Mandela was rushed to hospital in a 'serious' condition today following a recurrence of the lung infection that has plagued him in recent months.
The 94-year-old anti-apartheid leader, whose health has been failing in recent years, has been hospitalised three times since December.
Mandela was said to be in 'good spirits' but the situation was 'serious this time', a government spokesman told a South African news channel today.
Health issues: The former South African president was last photographed on April 29 (above) recuperating at home after being hospitalised with pneumonia
Ailing: President Jacob Zuma places a hand on Mandela's following the 94-year-old's release from his latest hospital stay in April
'The situation is serious this time but doctors have assured us he is comfortable,' presidential spokesman Mac Maharaj told television station eNCA.
Mr Maharaj said members of Mandela's family had accompanied him to the hospital in Pretoria and remained at his bedside.
His wife, Graca Machel, cancelled a scheduled appearance at a hunger summit in London today to remain at her husband's side.
Frail: Mandela is seen in April with President Jacob Zuma, who today wished the 94-year-old a speedy recovery
'Conscious': Mandela is believed to have been admitted to the private Mediclinic hospital in Pretoria, in South Africa's Gauteng Province
Fears: Members of the press were gathering today outside the Pretoria hospital where the former leader is believed to have been taken in the early hours of this morning
The wording of the government statement, in particular the use of the word 'serious', is clear cause for concern to South Africa's 53 million people, for whom Mandela remains a potent symbol of the struggle against decades of white-minority rule.
'Fighter': Nelson Mandela and his wife Graca Machel smile for the camera at their home in Qunu, South Africa, in August 2012 during an increasingly rare public appearance
Mandela has been vulnerable to respiratory problems since contracting tuberculosis during his 27 years behind bars under apartheid.
Doctors treat the matter with great caution, Mr Maharaj told the BBC, and Mandela is admitted to hospital 'as necessary' to give him the best opportunity to recover.
'He has been in good spirits. He is a fighter and he will be with us as long as he is there fighting,' Mr Maharaj added.
He told Sky News the former leader was conscious, 'able to breathe on his own', and 'communicating' with relatives at his bedside.
An earlier statement from the office of President Jacob Zuma said: 'During the past few days, former President Nelson Mandela has had a recurrence of a lung infection.
'This morning at about 1.30am, his condition deteriorated and he was transferred to a Pretoria hospital.'
The statement said Mandela remains in a 'serious but stable' condition.
It said Mandela, who will celebrate his 95th birthday next month, was receiving expert medical care and 'doctors are doing everything possible to make him better and comfortable'.
Zuma wished Mandela a quick recovery on behalf of the government and the nation and called for the former leader's privacy to be respected.
Using the former president's Xhosa clan name, the statement said: 'President Jacob Zuma, on behalf of government and the nation, wishes Madiba a speedy recovery.'
In Britain, Prime Minister David Cameron was among the first to send get well wishes to the former South African president, tweeting: 'My thoughts are with Nelson Mandela, who is in hospital in South Africa.'
'Beloved statesman': Hilary Clinton, then U.S. Secretary of State, is seen meeting with Mandela at his South African home in August 2012
The African National Congress (ANC), the ruling party that has dominated politics in South Africa since the end of apartheid, urged people across the world to keep 'our beloved statesman' in their prayers.
'The situation is serious this time but doctors have assured us he is comfortable'
Presidential spokesman
'We will keep President Mandela and his family in our thoughts and prayers at this time and call upon South Africans and the peoples of the globe to do the same for our beloved statesman and icon, Madiba,' the party said in a statement.
A spokesman for the party told Sky News the nation was 'prepared for the worst'.
'Madiba is the personification of humanity, friendship, honesty, integrity,' Jackson Mthembu told the brodadcaster.
'Without the calibre of Madiba's leadership, the likelihood is that South Africa would have gone to ruins ... but there was a Madiba.'
More messages of support for the former leader were flooding in from other political groups and unions today.
The Congress of South African Trade Unions (Cosatu) sent a message of goodwill to Mandela, the South African Broadcasting Corporation reported.
'Tata': Mandela, seen left at his Qunu home in May 2012, and right at an ANC rally ahead of the presidential elections in 2009, has struggled with respiratory problems since contracting tuberculosis while in jail
'Our 2.2 million members, thousands of working people, millions of South Africans and countless more freedom-loving people around the world are thinking of you today and wishing that you make a full recovery and soon return home,' it said in a statement.
The South African Communist Party wished Mandela a 'speedy recovery' and told the former president: 'You are in our thoughts'.
The Young Communist League (YCL) added: 'Tata is in our thoughts and we hope he will recover as soon as possible.'
Many South Africans use the term of endearment Tata - the Xhosa word for father - to refer to the ageing political icon.
Mandela's wife was due to address the Nutrition for Growth meeting in London this afternoon.
But Ms Machel's name was removed from the provisional list of speakers this morning with organisers saying she had to cancel 'for personal reasons'.
International figure: David Cameron, seen with Nelson Mandela during his visit to London in 2008, said today his thoughts were with South Africa's former leader
Well-wishers: Britain's prime minister was among those sending messages of support to Mandela today
Ms Machel was pencilled in to speak between 12.30 and 1pm alongside Bill Gates, Justine Greening the Secretary of State for International Development, and Chris Cooper-Hohn, of the Children's Investment Fund Foundation.
But as news emerged of Mr Mandela's treatment in hospital, the line-up was changed and Ms Machel's attendance cancelled.
The broadcaster Henry Bonsu, who is compering the event, said: 'She sends her apologies and regrets not being here to attend her session.'
South African Presidency spokesman Mr Maharaj confirmed Ms Machel had pulled out of the London trip on Thursday.
'She accompanied Madiba to hospital this morning and has been at the hospital since that time,' he said.
Ms Machel, 67, the former leader's third wife, was also due to attend a rally in London's Hyde Park demanding the G8 takes action on the causes of Third World hunger.
Brendan Cox, spokesman for the Enough Food For Everyone IF campaign, said: 'We're sad that Graca Machel was not able to attend the Big IF because of family reasons.
'Our thoughts are with her and her family.'
Hospitalised: Nelson Mandela, 94, was re-admitted to hospital in the early hours of this morning due to a recurring lung infection
Madiba: Mandela, seen left and right in Johannesburg in 2008, is revered as an anti-apartheid hero
Setback: People in South Africa today told of their hopes that the former leader, seen left in 2008 and right in 2003, would recover from his latest bout of ill health
Mandela was previously admitted to hospital in March, where doctors drained fluid from his lung area after diagnosing him with pneumonia.
The former president spent 10 days in hospital before being released on April 6.
Video footage was broadcast of Mandela - or Madiba as he is affectionately known in South Africa - back at home and surrounded by family and friends. It is the last time he has been seen in public.
Mr Zuma said at the time the former leader was in 'good shape', but he appeared silent and unresponsive in the footage.
It followed an earlier stint in hospital in December 2012 after Mandela developed a lung infection and gallstones.
South Africans today told of their hopes that Mandela would recover from his latest setback.
'He is going to survive,' said Willie Mokoena, a gardener in Johannesburg. 'He's a strong man.'
Another city resident, Martha Mawela, said she thought the former president would recover because: 'Everybody loves Mandela.'
Mandela's forgiving spirit and belief in racial reconciliation helped hold South Africa together at a time of extreme tension in the run up to elections in 1994.
The Nobel Peace Prize laureate, who was imprisoned for 27 years by the racist white regime, became the first democratically elected president of South Africa in that year.
Mandela was robust during his decades as a public figure, endowed with charisma, a powerful memory and an extraordinary talent for articulating the aspirations of his people and winning over many of those who opposed him.
In recent years, however, he has become increasingly frail. He didn't deliver an address during his last major public appearance at the 2010 World Cup soccer tournament, where he was bundled against the cold.
'Icon': Nelson Mandela and his former wife Winnie walk hand-in-hand with fists raised following his release from Victor Verster Prison near Cape Town in February 1990
Decades in the public eye: Mandela laughs as he shakes hands with South African President FW De Klerk prior to their internationally televised debate in Johannesburg in 1994
Since his withdrawal from public life, Mandela has divided his time between his plush Johannesburg home and Qunu, the village in the impoverished Eastern Cape where he was born and spent his early years.
Although he remains deeply revered, Mandela is not without his detractors both at home and in the rest of Africa.
Some of them feel he made too many concessions to the white minority in the post-apartheid settlement.
Despite more than 10 years of policies aimed at redressing the balance, whites still control much of the economy and an average white household earns six times more than a black one.
'Mandela has gone a bit too far in doing good to the non-black communities, really in some cases at the expense of (blacks),' Zimbabwean President Robert Mugabe, 89, said in a documentary aired on South African television this month.
'That's being too saintly, too good, too much of a saint.'
Mandela stepped down as president in 1999 and has not been politically active in a decade
