Nelson Mandela spent the night in hospital, months after being treated for a lung infection and gallstones, but the South African presidency gave no news on his condition. \"There isn\'t an update. I just have to allow the doctors to advise me,\" said presidential spokesman Mac Maharaj. One of Mandela\'s grand-nephews insisted that the former statesman was simply undergoing tests. \"It\'s a normal check up at the hospital as an old person,\" he told AFP. Maharaj could not say how long the former statesman would have to stay at the facility this time, after an 18-day hospitalisation in December. \"It all depends on the doctors,\" Maharaj told AFP. The presidency said Mandela, 94, was hospitalised Saturday for a \"scheduled medical checkup to manage the existing conditions in line with his age\". They did not divulge at which Pretoria hospital he was staying. But a witness told AFP that patients at the Mediclinic Heart Hospital were on Saturday moved out of the ward that Mandela stayed in during his December hospitalisation.  The hospital told them the ward needed to be repainted, but no one was allowed near the area, she said. Mandela underwent treatment for a recurrent lung infection and surgery to extract gallstones over Christmas, during his longest stint in hospital since his release from prison in 1990. He was discharged the day after Christmas and was last known to be convalescing at his home in Johannesburg. Mandela served one term as South Africa\'s first black president after winning historic all-race elections in 1994. Having spent almost three decades in prison for opposing apartheid, he is revered as the symbol of the country\'s peaceful shift into democracy after racist white minority rule. Mandela the man has grown increasingly frail in recent years, remaining out of the public eye at his rural home village in the Eastern Cape.