President Jacob Zuma said Nelson Mandela is "responding very well to the treatment" as he urged the country not to panic.
He told BBC News: "Of course I have been saying to people, you should bear in mind Madiba is no longer that young and if he goes for check-ups every now and again, I don't think people must be alarmed about it. I would like to really say the country must not panic."
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Cloud cover will keep temperatures overnight a little warmer than usual for this time of year. Expect some mist and fog by morning.