The president ended his first overseas trip in office by reaching out to Muslim youth in Turkey and elsewhere.
At a cultural center in Istanbul, Turkey's largest city, Mr. Obama took part in a question and answer session with about 100 students.
He said he wants to launch a dialogue not just with them, but with the wider Muslim world.
"… and I want you to know that I am personally committed to a new chapter of American engagement," he said. "We can't afford to talk past one another and focus only on our differences or to let walls of mistrust go up around us."
The president said simple exchanges can break down those walls. And, he started by speaking candidly with the young people in the room.
Trying to end the session before the afternoon Muslim call to prayer, he said there are many people outside of the United States that think of Americans only as selfish and crass. He said that is not the country he loves. And, he pointed to his own election as a sign that the nation is moving forward.
"I think people saw my election as proof, as testimony that, although we are imperfect, our society has continued to improve," he said.
Mr. Obama was asked if he really represents a change from the previous administration and if there is a new face at the White House, but the same old policies remain.
He said it takes time to move the ship of state and dramatic changes in foreign policy do not necessarily come overnight. But he spoke of his determination to end the war in Iraq and seek an international agreement on climate change as breaks with the past.
Mr. Obama has already announced changes in the way America treats terror detainees. But he said in Turkey that he will not relent in the ongoing effort to destroy al-Qaida.
"I don't make any apologies for continuing the effort to prevent bombs going off or planes going into buildings that would kill innocents," he said. "I don't think any society can justify that."
The president also used the opportunity to discuss the one issue that perhaps more than any other has shaped American ties with the Muslim world over the course of decades. Long before the Iraq war frayed relations, there were tensions over the Israeli-Palestinian peace process.
Speaking just days after a new hardline conservative government took power in Israel, Mr. Obama stressed the need for compromise on all sides.
"I think we have a sense of what those compromises should be and will be," he said. "Now, what we need is political will and courage on the part of leadership."
The gathering with students was the final event of an eight-day tour that White House officials consider enormously productive.
The president's top advisor, David Axelrod, says Mr. Obama moved to restore trust and mend frayed ties throughout his travels. He says it may take a while to see specific results. But he stresses the president's discussions abroad helped establish a basis for trust and understanding.
"There will be a harvest that will come at different times and in different ways, but the seeds were planted and that was the goal of this trip," he said.
The trip began with the G20 emergency economic summit in London, followed by a gathering of NATO members on the French-German border and a meeting with European Union leaders in Prague. It ended in Turkey, where Mr. Obama continued his outreach to the Muslim world and sought to repair bilateral ties frayed by the Iraq War.