President Barack Obama embarks on his first Middle East mission, seeking Arab backing for his bid to revive peace moves while a US confrontation steadily builds with staunch ally Israel.
The highlight of the trip will be a much-anticipated address to the Muslim world from Cairo, but Obama will also attempt to prod moribund regional peacemaking back to life.
He is first due in Saudi Arabia for talks with King Abdullah, who has been trying to relaunch a 2002 Arab-backed Middle East initiative, and heads Thursday to Egypt where he will meet President Hosni Mubarak.
Obama has said he will touch on the Middle East peace process in his Cairo University speech — a more general attempt to build bridges with Islam — but will not unveil a detailed plan.
The White House vowed to unleash all its technological and communications clout to ensure that as many people as possible see and hear the historic address, even through social networking sites.
On the eve of his trip, Al-Qaeda number two Ayman al-Zawahiri told Egyptians to shun Obama, saying his visit was at the invitation of the "torturers of Egypt" and the "slaves of America."
"His bloody messages were received and are still being received by Muslims, and they will not be concealed by public relations campaigns or by farcical visits or elegant words," Zawahiri said in an audiotape, according to the SITE Intelligence Group.
Egyptian democracy campaigners have criticised the choice of Cairo for such a major speech, saying Obama is rewarding an authoritarian government with a poor human rights record.
However, Obama is seen as uniquely positioned among US leaders to make inroads in the Islamic world.
The son of an African Muslim father, the president spent part of his childhood in majority-Muslim Indonesia. His middle name Hussein, which sometimes was seen as a liability on the campaign trail, doubtless will be viewed more charitably in many venues during his Middle East travels.
Obama has said he is confident of reviving meaningful Israeli-Palestinian talks, but the White House has been coy on his strategy, following a flurry of meetings with regional leaders in recent weeks.
The president has repeatedly backed a two-state solution to the conflict, despite Israeli Prime Minister Benjamin Netanyahu’s reluctance to embrace such a position and his defiant stance on Jewish settlements.
Obama, who last week met Palestinian president Mahmud Abbas, is expected to lobby Saudi Arabia and Egypt for gestures which would widen Netanyahu’s room for political manoeuvre.
"I think the administration is interested in the April 2002 Saudi plan," said Steven Cook of the Council on Foreign Relations.
The initiative calls for full normalisation of relations between Arab states and Israel, a full withdrawal by Israel from Arab land, the creation of a Palestinian state and an "equitable" solution for Palestinian refugees.
The Hamas Islamist group, which rules the Gaza Strip, has been told by the Middle East Quartet — the European Union, Russia, United Nations and United States — that it must recognise Israel, renounce violence, and abide by prior agreements made by the Palestinians, in return for a place at the table.
Some analysts see the 2002 plan as a way to broaden Middle East diplomacy and bypass the stalemated Israeli-Palestinian track.
King Abdullah II of Jordan has been pushing a "57-state" solution, which would grant Israel sweeping diplomatic recognition in return for making peace with the Palestinians.
So far though, it seems unlikely Arab states will grant early concessions to Israel without some moderation of Netanyahu’s position on Jewish settlements on occupied Palestinian land.
The issue has stoked tensions between Israel and Washington, with Obama using unusually strident tones to demand a halt to settlement construction.
"Being able to match the minimum that the Arabs would accept with the maximum that Netanyahu would actually be prepared to give is really a fool’s errand," said Flynt Leverett, a US official who left the Bush administration over differences on Middle East policy.
Obama will face questioning from Saudi King Abdullah on his plans to engage arch US-foe Iran, which some Saudis fear could result in a grand bargain which harms the oil powerhouse’s interests.
Some observers see an opportunity to exploit Arab disquiet about Iran’s nuclear drive to forge an Arab-Israeli compact, although such hopes have proven fruitless in the past.
"This is something that the Bush administration tried and failed. This is something that even the Clinton administration (tried) in its way," said Leverett, director of the Geopolitics of Energy Initiative at the New America Foundation.
US special Middle East envoy George Mitchell will travel to the region next week.