As President Obama prepares to depart for the Middle East to promote improved U.S. relations with Muslim nations, he has reaffirmed Iran's right to develop nuclear energy and met with Israeli Defense Minister Ehud Barak.

The president is not headed to Israel on his five-day tour, one of the most important trips of his fledgling presidency. Instead, he will arrive in Saudi Arabia on Wednesday and deliver a speech at Cairo University in Egypt on Thursday. He then travels to France and Germany for D-Day commemorations.

His face-to-face encounter with the Muslim world comes as he offers tough love to Israel, with whom he has recently offered tough words over settlements in the West Bank. Barak met with Obama and his national security adviser, Gen. Jim Jones, at the White House.

The details of that meeting were slight, but likely included discussion of Iran's claim to pursue nuclear energy -- a right it says it maintains as a member of the Nuclear Non-Proliferation Treaty.

Successive U.S. administrations have always affirmed that right insofar as Iran complies with treaty requirements to be open to inspections by the U.N.'s International Atomic Energy Agency.

Iran has flouted that criterion for decades, but without referring to it, Obama on Tuesday reaffirmed Tehran's right as long as the country proves by the end of the year that its aspirations are peaceful.

Obama told the BBC in an interview broadcast Tuesday that he believes "Iran has legitimate energy concerns, legitimate aspirations," adding that the international community also "has a very real interest" in preventing a nuclear arms race.

Such language, as well as Obama's upcoming speech, is critical to pressuring Iran to halt its uranium enrichment program, which the international community fears is a cover for building a nuclear bomb.

The Bush administration had insisted that Iran scrap enrichment before restoring diplomatic talks with the country that has been cut off from the U.S. since 1979's hostage crisis. Iran repeatedly has rejected the demand and expanded its enrichment activities, triggering three sets of U.N. Security Council sanctions.

But the recent overtures to Iran as well as remarks to the broader Middle East have left some speculating about whether the U.S. could also be distancing itself from Israel.

Obama has rejected the notion that efforts to engage the Arab world comes at the sacrifice of Israel, even as the president leans hard on the U.S. ally and only democratic nation in the Middle East.

Obama told National Public Radio Monday that the U.S. must "retain a constant belief in the possibilities of negotiations that will lead to peace.

"And that's going to require, from my view, a two-state solution that is going to require that each side -- the Israelis and Palestinians -- meet their obligations," he said.

Obama explained those obligations include Israelis freezing settlements and Palestinians continuing to make security gains and ending incitement that worries Israel.

"Part of being a good friend is being honest. And I think there have been times where we are not as honest as we should be about the fact that the current direction, the current trajectory in the region, is profoundly negative not only for Israeli interests but also U.S. interests. And that's part of a new dialogue that I'd like to see encouraged in the region," Obama said.

Foreign policy analysts say achieving any peace plan faces hurdles, particularly considering that Israeli Prime Minister Benjamin Netanyahu has already rejected Obama's call to freeze settlements. 

"We believe that the path (Obama) has outlined, which is driven by diplomacy, driven by a two-state solution, is both in the very interest of the United States and Israel," said Jeremy Ben-Ami, founder and executive director of J Street, "a pro-Israel, pro-peace" PAC.

Ben-Ami said the Obama administration faces a bigger risk by not drawing a line in the sand.

"The mark of a true friendship is really to be able to speak the truth to your friends in hard times," Ben-Ami said, arguing that the path Israel is on will lead to its ultimate demise.

Obama's "exactly right in saying stop. This is going to kill you. It's a matter of life and death."

Obama will deliver his speech at Cairo University, which White House officials call a bastion of secular Muslim thinking that reflects the side of Islam that the U.S. is appealing to in its case for a strategic partnership.

Denis McDonough, deputy national security advisor, said last week that the president wants to send a message -- one that he has repeated since his inauguration -- that the U.S. has been influenced by many advances by Muslims, including in math and science.. 

Still, White House Press Secretary Robert Gibbs played down expectations on Tuesday. 

"This is about resetting our relationship with the Muslim world. ... We don't expect everything to change after one speech," he said.

In an interview broadcast Tuesday on French television, Obama also warned against heightened expectations.

"I think it is very important to understand that one speech is not going to solve all the problems in the Middle East," Obama said. "And so expectations need to be somehow modest."

Nathan Brown, a political scientist at George Washington University, said Obama's demand that Israel freeze settlements will make Arab leaders pay close attention to his speech this week. 

"His predecessor, who did talk two-state solution, was not taken seriously because there was no change on the ground," he said, explaining that Muslims want to see something concrete go along with the platitudes

But Brown also warned that unless Obama has a clear follow up strategy, he could face the same problems as former President George W. Bush did in trying to deliver a peace plan.

Ben-Ami noted that U.S. opposition to Israeli settlements has been consistent since the Six-Day War, Israel's 1967 military victory over Egypt, Jordan and Syria. But past U.S. presidents have allowed Israel to continue building settlements. 

"I think the problem that has happened in the past is American administrations said 'no' and 'no' meant maybe or a little bit," Ben-Ami said. "I think 'no' has to mean 'no.'"

Ghaith Al-Omari, advocacy director for The American Task Force on Palestine, said Obama's hard-line approach with Israel would actually serve to undermine Iran's nuclear ambitions as well as improve Arab Muslim ties.

"If we move forward on a settlement freeze, it will make it easier to form a regional coalition against Iran," Al-Omari said.