But he also called on the Palestinians to “abandon violence,” holding up the U.S. civil rights movement as an example. “Resistance through violence and killing is wrong and does not succeed,” he said. “For centuries, black people in America suffered the lash of the whip as slaves and the humiliation of segregation. But it was not violence that won full and equal rights. It was a peaceful and determined insistence upon the ideals at the center of America ‘s founding.”

To strong applause from the audience, Obama quoted several times from the Koran, Islam’s scripture, and noted that American founding father Thomas Jefferson kept a copy of the book in his personal library. “As the Holy Koran tells us,” he said, “Be conscious of God and speak always the truth.”

He stressed the freedoms and successes that Muslims have experienced in the United States, and said: “Let there be no doubt. Islam is part of America.”

“There is a mosque in every state of our union, and over 1,200 mosques within our borders,” Obama said. ” . . . The U.S. government has gone to court to protect the right of women and girls to wear the hijab, and to punish those who would deny it.”

For security reasons, this famously raucous city was largely shut down in the hours leading up to the speech, with black-clad members of the Egyptian security forces stationed every 50 feet or so for miles outside the university. Roads usually snarled with traffic flowed as smoothly as country lanes. Security forces appeared to be blocking access into downtown from some poorer neighborhoods.

Obama arrived here from Riyadh, Saudi Arabia, just after 9 a.m. local time. He was greeted at the airport by Egypt’s foreign minister, Ahmed Aboul Gheit, and taken swiftly to Qubba Palace, where the motorcade was escorted up the long drive by 21 horses.

Egyptian President Hosni Mubarak, reviled by the political opposition here for his iron grasp on the media and the security forces he often deploys, joined Obama on a palace balcony for the welcoming ceremony, featuring each country’s national anthem. The two men then met privately for about 20 minutes.

Obama said afterward that, among other issues, the two leaders discussed the Israeli-Palestinian conflict and “how we can move forward in a constructive way that brings about peace and prosperity for all people in the region.” Mubarak said, through a translator, that the pair had discussed “all problems here in the region” including “the situation and everything related to Iran and to the region.”

“We discussed everything candidly and frankly without any reservation,” Mubarak said. “But there are other meetings that will take place later either in the United States of America or anywhere else.”

The administration has taken extraordinary steps to make sure Obama’s speech is heard around the world, including offering instant text-messaging of the address in four languages, creating special links on popular social networking sites, and facilitating its live broadcast on national television networks.

“There has been a breach, an undeniable breach between America and the Islamic world, and that breach has been years in the making,” said David Axelrod, a senior adviser to Obama. “It is not going to be reversed in one speech. It is not going to be reversed perhaps in one administration. But the president is a strong believer in open, honest dialogue.”

Egypt’s state-run television channel is covering Obama’s visit live, moment by moment. Footage of Egyptian and American flags standing side by side serves as visual wallpaper for viewers, many of whom gathered throughout a bright morning at cafes to watch the speech together. For a few hours, Egypt’s thriving Facebook generation has enjoyed the café camaraderie of earlier ones.

Hundreds of people who had been invited to hear the speech live had to pass through several layers of security to enter the grand domed building, a campus landmark.

Inside, two layers of balconies peer onto a stage where six pairs of Egyptian and American flags served as Obama’s backdrop. Red curtains matched the red carpets that ran along the aisles, and gold-leaf trim highlighted the arches and domes of the hall.

There were no obvious protests surrounding the visit, save one. The liberal activist group Code Pink held up a banner of the same color outside the university entrance that read “End the Siege of Gaza” in English and Arabic.

Egyptian security forces did nothing to stop the demonstration. But no Egyptian protesters were visible, a testament to Mubarak’s control and, perhaps, gratitude.

The attention surrounding Obama’s address and his first visit to Saudi Arabia was underscored Wednesday by a pair of messages from Osama bin Laden and his Egyptian deputy, Ayman al-Zawahiri.

Shortly after Obama landed in Riyadh, the Arab satellite network al-Jazeera aired an audiotape of bin Laden sharply criticizing U.S. policy in Pakistan and accusing Obama of planting seeds for “revenge and hatred” in the Muslim world. The message said Obama is following President George W. Bush’s policy of “antagonizing Muslims,” and bin Laden warned Americans of “consequences” to come. U.S. officials did not dispute the tape’s authenticity even though bin Laden, once a Saudi citizen, has not been seen for years.

A day earlier, Zawahiri urged Egyptians to shun Obama during his visit, saying his trip was at the invitation of the “torturers of Egypt” and the “slaves of America.” Zawahiri, a doctor by training, was imprisoned in Egypt for his radical Islamist political beliefs until 1984.

Briefing reporters here, White House press secretary Robert Gibbs said, “I don’t think it’s surprising that al-Qaeda would want to shift attention away from the president’s historic efforts and continued efforts to reach out and have an open dialogue with the Muslim world.”