Washington - President Barack Obama on Thursday ordered flags to fly at half-staff at the White House and public buildings, with the US in mourning over the death of "close friend" and anti-apartheid hero Nelson Mandela.
Obama's proclamation, which also extended to the White House, US foreign missions, military posts, naval stations and military vessels, was valid through sunset on Monday.
"Today, the United States has lost a close friend, South Africa has lost an incomparable liberator, and the world has lost an inspiration for freedom, justice, and human dignity -- Nelson Mandela is no longer with us, he belongs to the ages," he said in the document.
"Through his fierce dignity and unbending will to sacrifice his own freedom for the freedom of others, he transformed South Africa -- and moved the entire world.
"While we mourn his loss, we will forever honor Nelson Mandela's memory. He left behind a South Africa that is free and at peace with itself -- a close friend and partner of the United States. And his memory will be kept in the hearts of billions who have been lifted up by the power of his example."
Obama said he was ordering flags to be lowered as a "mark of respect for the memory of Nelson Mandela."
Obama paid a somber heartfelt tribute at the White House within 45 minutes of Mandela's death being announced.
America's first black president met Mandela only once, briefly, in 2005, but was inspired to enter politics by the anti-apartheid hero's example.