Nelson Mandela
Nelson Mandela is in Critical ConditionReuters

Former South African President Nelson Mandela, who has been admitted in a Pretoria hospital for the last two weeks, is in a serious condition.

"The condition of former president Nelson Mandela, who is still in hospital in Pretoria, has become critical," informed presidential spokesman Mac Maharaj, reported Agence France-Presse (AFP).

The 94-year-old anti-apartheid revolutionary was admitted to Mediclinic Heart Hospital in Pretoria for lung infection earlier this month. His condition is said to have has worsened in the past 24 hours.

President Zuma, who went to the visit Mandela on Sunday evening,  said, "The doctors are doing everything possible to get his condition to improve and are ensuring that Madiba is well-looked after and is comfortable. He is in good hands."

In this crucial hour, Zuma further appealed fellow South Africans to pray for Mandela and his family.

Prayers continue to pour in from across the world for Mandela, who would turn 95 on 18 July. He also received well wishes from the White House. "We have seen the latest reports from the South African government that former president Mandela is in critical condition. Our thoughts and prayers are with him, his family and the people of South Africa," National Security Council spokeswoman Caitlin Hayden stated.

Meanwhile, US President Barrack Obama is to leave for an Africa tour on Wednesday. A meeting between Obama, America's first black president, and Mandela, South Africa's first black president, is eagerly anticipated. The Obama team has not yet announced any meeting schedule with the frail revolutionary yet.

Mandela's hospitalisation has raised several concerns after it came to light that the ambulance carrying him to hospital on 8 June had broken down. The second ambulance reached after a gap of 40 minutes, during which Mandela was at the mercy of paramedics.  

This is the fourth time Mandela has been admitted to hospital since December for pulmonary infections.