Former South African president Nelson Mandela has been admitted to hospital for tests today.

A statement from the South African government gave no details but said that there was no cause for alarm about the health of the 94-year-old anti-apartheid leader.

Mr Mandela became South Africa's first black president after the country's first all-race elections in 1994.

He was admitted to hospital in February because of abdominal pain but released the following day after a keyhole examination showed there was nothing seriously wrong with him.

Mr Mandela has since spent most of his time in his ancestral home in Qunu, a village in the impoverished Eastern Cape province.

His frail health prevents him from making any public appearances in South Africa, although in the last few months he has continued to receive high-profile visitors, including former US President Bill Clinton.