Zuma was addressing the media in Johannesburg on Monday, where he spoke at length about issues facing the youth and the economy.

However, with the overwhelming interest in Mandela's condition, Zuma confirmed a statement released on Sunday, saying the former president's condition remains critical.

"Madiba's health changed in 24 hours and he is now critical. I visited Madiba in hospital. I was with the [ANC] deputy president Cyril Ramaphosa at the time. Given the hour, he [Madiba] was already asleep. We were there, we saw him. We had a discussion with the doctors and his wife Graça Machel."

"I don't think I'm in a position to give further details. I'm not a doctor … but [his condition] remains the case up to now."

The presidency on Sunday warned against false hope for a recovery for the 94-year-old elder statesman.

In various interviews throughout Sunday morning, presidential spokesperson and close friend to Mandela, Mac Maharaj said the government would continue its policy of not disclosing clinical details but said a "sombre mood" would be appropriate at this time.

Outside the Mediclinic Heart Hospital in Pretoria, media from around the world maintained a vigil – keen for any detail or visuals for eager audiences. After two weeks in hospital, news of Mandela's health largely dropped off the global news agenda but it again lead bulletins and newspapers in countries ranging from Singapore to the United States on Sunday night and Monday morning.

Passers-by at the hospital, mostly on their way to work early on Monday morning, expressed the same range of views that had become common-place in previous weeks: prayers, well-wishes, the hope that Mandela will be returning home (and even to active politics soon), as well as concern that Mandela was effectively being denied peace.

"They shouldn't keep him alive if it's his time. It's cruel, it's not right," said a woman who did not wish to be named.

Tight security
Meanwhile, several police officers were manning the entrances to the hospital on Monday morning.

Before 6am, three police officers stood at the hospital's entrance along the busy Park Street.

The officers searched cars entering the hospital. More officers were inside the facility.

The hospital's other entrance along Celliers Street was opened before 6am. Police officers and hospital security searched all vehicles, including delivery vans.

Well-wishers adorned the hospital's security wall with get-well cards, balloons, flowers and paintings.

Some of the messages pasted onto the wall read: "Descendants of [former Ghana leader] Kwame Nkrumah wish u long life. Bernard [from] Ghana".

'We love you'
Another message imprinted on an Ethiopian flag read: "We love you our father, Tata Madiba".

A colourful card from a Montessori pre-school was decorated with tiny children's palm prints and numerous pictures of Madiba holding the Fifa World Cup trophy.

Several news crews converged on the hospital on Sunday night after the presidency announced that Mandela's condition deteriorated. Most of them left by 3am on Monday.

But more than 20 vehicles, including the broadcast vans for local and international media, occupied the parking along Celliers Street on Monday morning.

A few reporters braved the biting early morning cold to chat near the hospital's Park Street entrance.

It was a quiet night outside Mandela's home in Johannesburg with almost no movement on Monday morning.

Visitors
Shortly after 2am, a silver Jeep arrived at the house. The driver pulled up outside the black gates, flashed the vehicle's headlights and, when there was no response, hooted twice. The gates opened.

Two broadcasting teams arrived at the house on Sunday night, but left a short while later.

The street was otherwise quiet, with only the occasional armed response patrol.

After 6am the streets became busier as people continued with their daily routines. A black VW Polo parked outside the gate of the house and a woman entered.

On Sunday evening presidential spokesperson Mac Maharaj said in a statement: "The condition of former president Nelson Mandela, who is still in hospital in Pretoria, has become critical".

'Critical'
It was issued after a visit by President Jacob Zuma and ANC deputy president Cyril Ramaphosa.

"They were briefed by the medical team who informed them that the former president's condition had become critical over the past 24-hours," said Maharaj.

Zuma and Ramaphosa also met Mandela's wife Graça Machel to discuss his condition.

"The doctors are doing everything possible to get his condition to improve and are ensuring that Madiba is well-looked after and is comfortable," Zuma said in the statement. "He is in good hands."

Zuma appealed to South Africans to continue praying for Mandela and his medical team.

Mandela was admitted to hospital on June 8 for treatment of a recurring lung infection. – Additional reporting by Sapa