Johannesburg: Former South African president Nelson Mandela has been readmitted to hospital with a recurrence of a lung infection.

It marks the second hospitalisation for the ailing 94-year-old in two months.Mr Mandelas medical condition was “serious this time”, as told by government spokesman.

“Doctors have assured us he is comfortable,” presidential spokesman added.On April 16, he was released from hospital after being treated for pneumonia during a 10-day stay.

“This morning at about 1.30am his condition deteriorated and he was transferred to a Pretoria hospital. He remains in a serious but stable condition,” the presidents office said in a statement.

President Jacob Zuma also wished Mr Mandela a speedy recovery.

Increasingly frail, Mr Mandela remains one of the worlds most beloved figures even as his public appearances have become rare.