Washington - President Barack Obama will attend the national memorial service in Johannesburg on Tuesday for former South African president Nelson Mandela who died on Thursday, the White House said.

Other details of the trip and the US delegation will be announced soon, the White House said on Saturday.

Obama and his wife, Michelle, will be joined by former president George W. Bush and his wife, Laura, on Air Force One on the trip to South Africa next week, the White House said on Friday. Former president Bill Clinton will also attend Mandela events in South Africa, but his travel plans have not been announced.

There has been an outpouring of tributes from Americans to the 95-year-old Mandela, whose battle against white minority rule in South Africa was followed closely in the United States and helped fuel Obama's interest in politics.

A state funeral will take place on Sunday, December 15, at Mandela's home.