The report that the health of the 94-year-old anti-apartheid leader had taken a turn for the better came amid a growing sense in South Africa that Mandela was approaching the end of his life. Well-wishers have delivered flowers and messages of support to the Pretoria hospital where he is being treated, and prayer sessions were held around the country on Thursday.
President Jacob Zuma's office said in a statement that he received the encouraging update from the medical team that is treating Mandela. Zuma had canceled an international trip on Thursday, instead visiting Mandela for the second time in two days.
"I canceled my visit to Mozambique today so that I can see him and confer with the doctors," Zuma said in the statement. "He is much better today than he was when I saw him last night."
In April, Zuma gave an overly upbeat assessment about Mandela's condition. At that time, state television broadcast footage of a visit by Zuma and other political leaders to Mandela's home. Zuma said at the time that Mandela was in good shape, but the footage showed him silent and unresponsive, even when Zuma tried to hold his hand.
Mandela, who was imprisoned for 27 years during white racist rule and became president in all-race elections in 1994, was taken to a hospital on June 8 for what the government said was a recurring lung infection.
Zuma urged people to pray for Mandela, and continue with their work and daily activities even while he is hospitalized.
The president's office said it was disturbed by what it called rumors about Mandela's health and appealed for respect for the privacy and dignity of the former leader. Unconfirmed reports about Mandela have swirled on social media and other forums.
Mandela's condition is acknowledged to be grave. He is on life support systems, according to a few television networks that quote anonymous sources, and presidential spokesman Mac Maharaj has declined to confirm or deny those reports.
Makaziwe Mandela, one of Mandela's daughters, echoed the criticism, saying foreign media coverage of her father's illness had become intrusive, particularly at the Pretoria hospital where many journalists have gathered.
"There's sort of a racist element with many of the foreign media, where they just cross boundaries," she said in the SABC interview. "It's like truly vultures waiting when a lion has devoured a buffalo, waiting there for the last carcasses. That's the image that we have, as a family."
She said: "We don't mind the interest. But I just think it has gone overboard."
In comments posted on the SABC web site, Makaziwe Mandela said "anything is imminent" because her father, referred to affectionately by many South Africans as "Tata," or "Father," is in a very critical state.
"I want to emphasize again that it's only God who knows when the time to go is," she said. "So we will wait with Tata. He's still giving us hope by opening his eyes, he's still reactive to touch, we will live with that hope until the final end comes."
Beginning a trip to Africa, President Barack Obama said in Senegal on Thursday that his thoughts and prayers were with South Africans and in particular the Mandela family. He said he was inspired, as a law school student in the early 1990s, to see Mandela step forward after decades of imprisonment to help deliver democracy in a spirit of reconciliation with his former captors.
"It gave me a sense of what is possible in the world when righteous people, when people of good will, work together on behalf of a larger cause," said Obama, who described Mandela as a personal hero. "And if and when he passes from this place, one thing I think we'll all know is that his legacy is one that will linger on throughout the ages."