JOHANNESBURG - Visiting US President Barack Obama met with anti-apartheid icon Nelson Mandela's family on Saturday.

The meeting, which lasted for about half an hour, took place at the Nelson Mandela Center of Memory in Johannesburg.

Obama was accompanied by his wife Michelle Obama, but it remains unclear which Mandela family members took part in the meeting.

Obama said earlier he would not visit Mandela who is in critical but stable condition in hospital.

The White House said the decision was made in accordance with the wishes of Mandela's family. Obama himself said he didn't want to be "obtrusive" when Mandela is laying in bed.

Obama's visit, his second to South Africa but first as US president, is overshadowed by the ill health of Mandela.

After talks with the South African President Jacob Zuma earlier in the day, Obama lauded Mandela for his outstanding contributions to South Africa.

It was "great" to see what was happening in South Africa, when so many other regions were divided by conflict and disputes, Obama said.

Obama wished a quick recovery for Mandela who spent his 22nd day in hospital for a recurring lung infection.

Mandela's condition remains critical but stable after showing some improvement in the past two days, according to Zuma who issued the latest update on Mandela's health after talks with Obama.

The government hopes that Mandela, 94, will be out of hospital soon, Zuma said.

Meanwhile, according to a statement from the White House, Obama has also talked to Mandela's wife by telephone on Saturday.