It was the third time in four months that Mr. Mandela, 94, South Africa’s first black president and former leader of the dominant African National Congress, had been hospitalized. He was admitted shortly before midnight on Wednesday, the statement said, but the authorities delayed the announcement for several hours. The episode rekindled worries about his frailty.
Mr. Mandela spent 19 days in December hospitalized for a lung infection and what government officials described as the surgical removal of gallstones. He was readmitted earlier this month for what was termed a scheduled checkup.
Mr. Mandela has struggled with lung problems since he contracted tuberculosis during his 27 years in prison in the apartheid era, when his incarceration became a potent symbol in South Africa and around the world of the struggle to throw off a codified system of racial domination devised by the country’s white rulers.