South African President Cyril Ramaphosa is receiving treatment for mild Covid-19 symptoms after testing positive for the disease.
Mr Ramaphosa started feeling unwell and a test confirmed Covid-19, according to a statement from the presidency.
He is self-isolating in Cape Town and is being monitored by the South African Military Health Service, the statement said.
He has delegated all responsibilities to Deputy President David Mabuza for the next week.
Last week, Mr Ramaphosa visited four West African countries. He and all members of his delegation were tested for Covid-19 in each of the countries during the trip.
Some in the delegation tested positive in Nigeria and returned directly to South Africa.
Throughout the rest of the trip, Mr Ramaphosa and his delegation tested negative. Mr Ramaphosa returned from Senegal on December 8.
Mr Ramaphosa said his own infection serves as a warning to all people in South Africa to be vaccinated and remain vigilant against exposure, the statement said. Vaccination remains the best protection against severe illness and hospital admission, it said.
People in South Africa who have had contact with Mr Ramaphosa on Sunday are advised to watch for symptoms or to have themselves tested.
South Africa is battling a rapid resurgence of Covid-19 driven by the Omicron variant.
The country recorded more than 18,000 new confirmed cases on Sunday night. More than 70% of the cases are estimated to be from Omicron, according to genetic sequencing.
After a period of low transmission of about 200 new cases per day in early November, South Africa Covid-19 cases began rising dramatically.
On November 25, scientists in southern Africa confirmed the Omicron variant, which has more than 50 mutations.
Omicron appears to be highly transmissible and has quickly become dominant in the country. So far, the majority of cases have been relatively mild and the percentage of severe cases needing oxygen have been low, said doctors.