South Africa's former President Nelson Mandela is "doing very, very well" while undergoing unspecified medical tests at a military hospital, the nation's defence minister said Monday.

Minister Nosiviwe Mapisa-Nqakula stopped to speak to journalists outside of 1 Military Hospital in South Africa's capital, Pretoria, after seeing Mandela, 94, who has been hospitalized there for three days. She offered the first government confirmation that Mandela, who has received military medical care since 2011, is at that hospital.

"He's doing very, very well," the minister said in brief comments. "And it is important to keep him in our prayers and also to be as calm as possible and not cause a state of panic because I think that is not what all of us need."

A statement later issued Monday by the office of President Jacob Zuma also confirmed that Mandela is fine, but did not offer further details.

"Mandela had a good night's rest," the statement by presidential spokesman Mac Maharaj says. "The doctors will still conduct further tests today. He is in good hands."

On Saturday, Zuma's office announced Mandela had been admitted to a Pretoria hospital for medical tests and care that was "consistent for his age." Zuma visited Mandela on Sunday morning at the hospital and found the former leader to be "comfortable and in good care," presidential spokesman Mac Maharaj said in a statement. Maharaj offered no other details about Mandela, nor what medical tests he had undergone since entering the hospital.

In February, Mandela spent a night in a hospital for a minor diagnostic surgery to determine the cause of an abdominal complaint. In January 2011, Mandela was admitted to a Johannesburg hospital for what officials initially described as tests but what turned out to be an acute respiratory infection.

Mandela has had other health problems. He contracted tuberculosis during his years in prison and had surgery for an enlarged prostate gland in 1985. In 2001, Mandela underwent seven weeks of radiation therapy for prostate cancer, ultimately beating the disease.

Mandela, who spent 27 years in prison for fighting racist white rule, became South Africa's first black president in 1994 and served one five-year term. The Nobel laureate later retired from public life to live in his remote village of Qunu, in the Eastern Cape area, and last made a public appearance when his country hosted the 2010 World Cup soccer tournament. He has grown increasingly frail in recent years.