Former president of South Africa Nelson Mandela arrives at a hotel in central London, Monday, June 23, 2008. Mandela arrived in London Monday for a week of events to celebrate his 90th birthday, including an outdoor concert in his honor at Hyde Park on Friday with Proceeds going to his 46664 charity.(AP Photo/Akira Suemori)
(CNN) -- Former South African President Nelson Mandela's condition continues to improve, the country's presidential office said.
Mandela, 94, was readmitted last week to an unidentified hospital due to a recurring lung infection.
He received treatment for pneumonia over the weekend, a government spokesman said Saturday.
Doctors withdrew excess fluid that had accumulated in the space surrounding Mandela's lungs as a result of an infection, said Mac Maharaj, a spokesman for President Jacob Zuma.
Praying for Mandela's recovery
Look back at Mandela's early years It's the second time in past month Mandela has been hospitalized. More than two weeks ago, he was taken to a hospital for what officials described as a routine checkup.
He underwent treatment for a lung infection and had surgery to remove gallstones over the Christmas holiday -- one of his longest hospital stays since his release from prison in 1990.
The Nobel Peace Prize winner has become increasingly frail over the years and has not appeared in public since South Africa hosted the World Cup in 2010.
His history of lung problems dates back to when he was a political prisoner on Robben Island during apartheid. He contracted tuberculosis during the 27 years he was imprisoned.