(CNN) -- Former South African leader Nelson Mandela's health is improving, but he is still in serious condition, President Jacob Zuma said in a written statement Thursday.
Mandela, 94, has been in serious but stable condition since being rushed to a Pretoria hospital Saturday with a recurring lung infection, the president's office has said.
Zuma, who visited Mandela in his hospital room Thursday, asked South Africans to keep him in their thoughts.
"We continue to appeal to people to keep Madiba in their prayers and wish him a speedy recovery," he said. Madiba is Mandela's clan name, widely used in South Africa as a term of respect for him.
A statement from the Cabinet said Mandela has the best medical care possible.
Mandela's daughter and two grandchildren visited him in the hospital Thursday, according to the South African Press Association.
Mandela has been in and out of hospitals in recent years. Each episode has sparked renewed health concerns.
His history of lung problems dates to when he was a political prisoner on Robben Island during the apartheid era, and he has battled respiratory infections over the years.
He has not appeared in public since South Africa hosted the World Cup in 2010.
Last year, he spent the Christmas holidays undergoing treatment for a lung infection and gallstones, one of his longest hospital stays since his release from prison in 1990.
CNN's Pierre Meilhan, Errol Barnett and Kim Norgaard contributed to this report.