Nelson Mandela's health improving: Zuma

Nelson Mandela's health has improved but his condition remained serious, South African President Jacob Zuma has said, as the 94-year-old anti- apartheid icon spent his seventh day in hospital battling a recurrent lung infection.

Zuma and African National Congress Treasurer-General Dr Zweli Mkhize visited Mandela at the Mediclinic Heart Hospital in Pretoria last evening.

"Madiba's health continues to improve but his condition remains serious. We continue to appeal to people to keep Madiba in their prayers and wish him a speedy recovery," Zuma said using Mandela's clan name.

Mandela's daughter, Zinzi Mandela, also visited the ailing statesman yesterday.

About 12 bishops today held a prayer vigil outside the hospital where Mandela has spent a week receiving treatment for a lung infection.

"Thank you (God) for the speedy recovery of Dr Nelson Mandela," Bishop Abraham Sibiya of the Christ Centred Church Episcopal Soshanguve said.

Meanwhile, schoolchildren in Mandela's home village of Qunu sang songs in his honour. Many wellwishers also left balloons and well wishes outside the hospital where he is being treated.

This is Mandela's fourth hospitalisation since December.

Mandela has a long history of lung problems, dating back to the time when he was a political prisoner on Robben Island during apartheid. He contracted tuberculosis in 1988 during his 27 years in prison.

In December last year, he was admitted for 18 days for treatment of the lung infection and surgery to extract gallstones. It was his longest stint in hospital since his release from prison in 1990.

In March, he was admitted for an overnight scheduled check-up before returning to the hospital that month for 10-days.

Mandela, who turns 95 next month, has not been seen in public since the World Cup final in South Africa in July 2010.

Mandela, one of the world's tallest statesmen, led the movement to replace the apartheid regime of South Africa with a multi-racial democracy.

Mandela served as South Africa's first black president from 1994 to 1999. He won the Nobel Peace Prize in 1993.