Former South African President Nelson Mandela remains in the hospital for a fifth day.

The 94-year-old icon was hospitalized on Saturday for a recurring lung infection.

Two of Mandela's daughters and his former wife visited the hospital where Mandela is staying on Tuesday. President Jacob Zuma called Mandela's situation "very serious" but said he has stabilized.

Mandela, the leader of South Africa's anti-apartheid movement, spent 27 years in prison during white racist rule. He was freed in 1990, and then embarked on peacemaking efforts during the tense transition that saw the demise of the apartheid system and his own election as South Africa's first black president in 1994.

His admission to a hospital in Pretoria, the capital, is Mandela's fourth time being admitted to a hospital for treatment since December.