Mandela's health: Jacob Zuma sings for ex-president

South Africa's President Jacob Zuma has sung a rousing anti-apartheid song for Nelson Mandela, 94, who is critically ill in hospital.

Speaking at a conference of the National Education, Health and Allied Workers' Union (Nehawu), he said people must keep Mr Mandela and his family in their thoughts and prayers.

Mr Zuma said Mr Mandela's 95th birthday on 18 July would be celebrated with "vigour as it is a life spent in dedication to humanity".