U.S. President Barack Obama's surprise handshake Tuesday with Cuban President Raul Castro at a memorial for the late Nelson Mandela in South Africa was saluted in Havana as a hopeful sign.

The government website Cubadebate.cu ran a photograph of the moment with the caption: "Obama greets Raul: may this image be the beginning of the end of the U.S. aggressions against Cuba."

President Barack Obama has hired senior Democratic strategist John Podesta to try to get his troubled second term back on course, The Washington Post reported late Monday.

Podesta, 64, served as chief of staff to Bill Clinton when he was president and will work for Obama for a year as an adviser in his inner circle, the Post said, quoting sources familiar with the move.

A great unifier in life, in death Nelson Mandela will again bring together political foes Tuesday, when U.S. President Barack Obama and Cuban leader Raul Castro share a stage at his memorial.

Organizers announced Monday that the two men would be among world leaders to address a crowd of 80,000 people amassed at a stadium in Soweto and millions more watching on from around the world.

U.S. President Barack Obama headed to South Africa on Monday for the memorial service for anti-apartheid icon Nelson Mandela, according to an Agence France Presse journalist aboard Air Force One.

First lady Michelle Obama, former president George W. Bush and his wife Laura, and former secretary of state Hillary Clinton were also aboard the presidential jet.

President Barack Obama said Saturday that the United States had concluded it was possible for a two-state Middle East peace solution to include sufficient guarantees to preserve Israeli security.

Obama said the determination had been made by the U.S. special envoy on security, General John Allen, who has been briefing Israeli Prime Minister Benjamin Netanyahu on possible security arrangements following any final peace deal.

U.S. President Barack Obama warned Saturday that an "ideal" agreement to eliminate "every nut and bolt" of Iran's disputed nuclear program was not a realistic goal.

But he argued that the best possible available agreement with Tehran was likely to be better than the alternatives, and it was therefore imperative to try to secure one.

When U.S. President Barack Obama joins a roll-call of world leaders at next week's memorials for late South African president Nelson Mandela he will honor a personal inspiration.

Many international statesmen have been keen to associate themselves with the revered anti-apartheid fighter, but Obama can cite a convincing precedent for claiming Mandela's influence.

President Barack Obama on Thursday defended his nuclear diplomacy with Iran before an audience of Israeli diplomats and senior members of the U.S. Jewish community and officials.

At a White House Hanukkah reception, Obama said that it was important for the United States to test Iran's intentions, and pledged to keep working for a comprehensive deal to deprive Tehran of a nuclear weapon.

America's first black president Barack Obama Thursday mourned Nelson Mandela as a "profoundly good" man who "took history in his hands and bent the arc of the moral universe towards justice."

Obama -- who met the former South African president briefly only once in 2005, but was inspired to enter politics by the anti-apartheid hero's example -- paid a somber heartfelt tribute within 45 minutes of Mandela's death being announced.

The death of South Africa's liberation leader Nelson Mandela has unleashed a heartfelt chorus of awed respect from across the worlds of politics, religion, sport and culture.

Statesmen, resistance leaders, Nobel laureates and prisoners of conscience have died before, but never has one man united such global unity in honoring his passing.