South Africa's Nelson Mandela takes a turn for the worse

(CNN) -- Former South African President Nelson Mandela is now in critical condition, officials said.

Mandela's condition worsened in the past 24 hours, the South African president's office said, citing Mandela's medical team.

He has been hospitalized in Pretoria since June 8 for a recurring lung infection. Previously, authorities had described his condition as serious but stable.

"The doctors are doing everything possible to get his condition to improve and are ensuring that Madiba is well-looked after and is comfortable. He is in good hands," President Jacob Zuma said in a written statement, referring to Mandela's tribal name.

Mandela, 94, has become increasingly frail over the years and has not appeared in public since South Africa hosted the World Cup in 2010.