WASHINGTON - President Barack Obama will try to repair America's tarnished image in the Muslim world on Thursday, as he looks to mobilize support for restarting Middle East peacemaking and thwarting Iran's nuclear ambitions.

In a highly anticipated speech in Cairo, Obama will reach out to the world's more than 1 billion Muslims, seeking to chart a new path in U.S.-Muslim relations that were badly damaged by the Bush administration's global war on terror.

I want to use the occasion to deliver a broader message about how the United States can change for the better its relationship with the Muslim world, Obama said last week after meeting Palestinian President Mahmoud Abbas in Washington.

But analysts say Obama will be trying to win over Muslims in the Middle East, where he faces some of his biggest foreign policy challenges, from the Iraq war and the nuclear standoff with Iran to the Palestinian-Israeli conflict.

The U.S.-led invasions of Afghanistan and Iraq, the treatment of prisoners at the U.S. military prison at Guantanamo and Abu Ghraib prison in Iraq, and the Bush administration's perceived bias in favor of Israel stoked anti-American sentiment in the region and fueled terrorism.

The best he could hope to accomplish is move Arab public opinion about the United States and make it easier for their governments to work with (Washington). We need it for our general influence in the area, said Elliott Abrams, a senior fellow at the Council on Foreign Relations who served in senior foreign policy positions under two Republican presidents.

The speech comes at a time when Obama is seeking to build an alliance of moderate Muslim nations to pressure Iran to stop uranium enrichment, which Washington fears is a cover to build atomic weapons but Tehran says is for peaceful purposes. He also needs their support for renewed U.S.-led efforts to seek a two-state solution to the Palestinian-Israeli conflict.

His administration has embraced a proposal by Saudi Arabia that offers Israel normal ties with all Arab states in return for a full withdrawal from the lands it seized in the 1967 Middle East war, creation of a Palestinian state and a just solution to the Palestinian refugee problem.

It will likely feature in Obama's talks with Saudi King Abdullah in Riyadh on Wednesday on his way to Egypt,

How the United States addresses the conflict is how citizens of the region are likely to regard the United States, said Steve Grand, an expert on U.S.-Islamic relations at the Brookings Institution. That more than anything binds Muslims into what many call the Muslim world.

Obama spent last week working with aides to craft the speech, which he has said will address the Palestinian-Israeli question, but possibly not in the detail that many Muslims would like. The White House has already dismissed speculation he will unveil a new Middle East peace initiative.

LOCATION, LOCATION, LOCATION

But Muslims are looking for Obama to move beyond rhetorical flourishes to tell them how he plans to improve relations and to what extent he embraces former President George W. Bush's drive for democracy in a region rife with authoritarian governments.

He has been great at a rhetorical level, but he has to provide details about what the United States is going to concretely do to reach out to the Muslim world, Grand said.

Diaa Rashwan, an analyst at Cairo's Ahram Center for Political and Strategic Studies, is more skeptical.

He will speak only in general terms to give the impression that America is not the enemy of the Arab and Muslim world. He will not be specific, Rashwan said.

But just as important as what Obama says is where he is giving the speech.

By choosing Egypt, one of only two Arab states to sign a peace deal with Israel and a longtime strategic ally of Washington in the region, Obama is sending an important signal on his commitment to reviving stalled Middle East peace talks, said Daniel Brumberg of the U.S. Institute of Peace.

The choice of Cairo is the message, Brumberg said.

Obama will have to tread carefully in his speech to avoid the appearance that he is endorsing President Hosni Mubarak, whose government is accused of having a poor human rights record and of cracking down on political opponents.

Former U.S. Secretary of State Condoleezza Rice famously angered the Egyptian government when she gave a speech in Egypt in 2005 in which she targeted its human rights record.

Obama administration officials said Obama would not hesitate to raise civil society and democracy issues in talks with Mubarak, while his speech would address the full range of issues such as the importance of prosperity and freedom.

The White House has also defended the choice of Cairo, saying the speech is more important than the location.

Obama will deliver the speech at Cairo University in an event co-hosted by al-Azhar University, the chief center of Islamic and Arabic learning in the world. Invitees will include Egyptian political actors, the administration officials said, while declining to say whether opposition and human rights activists would be among them.

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