South Africans are heading to work in a sombre mood as they await news on former President Nelson Mandela.

The South African presidency announced on Sunday evening that Mandela had become critical, even though doctors were "doing everything possible".

A senior official said South Africans should not hold out "false hopes".

Mandela was taken to hospital in Pretoria earlier this month for the third time this year, with a lung infection.

President Jacob Zuma said on Sunday that he had visited him and spoken to his wife and medical teams.

Zuma said he had been told by doctors that the former president's condition had worsened over the past 24 hours.

Agencies