Former South African President Nelson Mandela is "responding positively" to treatment for a recurring lung infection after he was taken to a hospital late Wednesday, the presidency said on Thursday.
"The doctors advise that former President Nelson Mandela is responding positively to the treatment he is undergoing for a recurring lung infection," the presidency said in a statement. "He remains under treatment and observation in hospital."
In a statement, the current South African President Jacob Zuma said, “We appeal to the people of South Africa and the world to pray for our beloved Madiba [a nickname for Mandela] and his family and to keep them in their thoughts.”
“We have full confidence in the medical team and know that they will do everything possible to ensure recovery,” he added. “The Presidency appeals once again for understanding and privacy in order to allow space to the doctors to do their work.”
Mandela, 94, was taken to a hospital just before midnight local time (6 p.m. ET).
The statement said that Mandela had the “best possible expert in medical treatment and comfort.”
Mandela has a history of lung problems dating back to when he contracted tuberculosis as a political prisoner in the notorious Robben Island jail under the apartheid regime.
Jackson Mthembu, a spokesman for the African National Congress, said in a statement that the party once led by Mandela “calls on all South Africans and the world to keep Nelson Mandela in their prayers.”
“We are confident that the treatment will be successful as he is in professional and competent hands,” he said.
“During these trying times we wish President Mandela well and for his family to be strong," he added.
Mandela spent nearly three weeks in a hospital in December for treatment of a lung infection and gallstone surgery.
This was the longest time he had been hospitalized since being released from captivity as a political prisoner in 1990.
He was also hospitalized earlier this month for what was described as a "scheduled medical checkup."
Mandela was president of South Africa from 1994 to 1999, the first president of the country to be elected following the fall of the apartheid system.
President Barack Obama sent his best wishes to the former leader on Thursday.
"He is as strong physically as he's been in character and in leadership over so many decades, and hopefully he will ... come out of this latest challenge," Obama told reporters at the White House.
"When you think of a single individual that embodies the kind of leadership qualities that I think we all aspire to, the first name that comes up is Nelson Mandela. And so we wish him all the very best," Obama said.
NBC News' Matthew DeLuca and Rohit Kachroo, and Reuters contributed to this report.