Ankara - US President Barack Obama left Turkey on Tuesday at the end of his first major foreign tour, with White House officials saying the trip had been a major success.

Obama's senior advisor, David Axelrod, said that "it was a great success, an enormously productive journey," on Tuesday in Istanbul. Axelrod highlighted the new trust gained between the US president and the Russian and Chinese presidents, Dmitry Medvedev and Hu Jintao.

Obama wrapped up his trip with a two day visit to mainly- Muslim Turkey to improve US standing in the Islamic world.

"I came to Turkey because I am deeply committed to rebuilding a relationship between the United States and the people of the Muslim world. One that is grounded in mutual interest and mutual respect," Obama said at the meeting held in an Ottoman-era building in Istanbul.

The president took questions from students, and admitted that US ties in the region have been frayed, especially due to the war in Iraq.

One student pointed out that Turkey and the wider Muslim community fear that Obama's election is a superficial change and that US policies in the region will not change.

Obama responded by pointing out that he was against the war but now had the responsibility to withdraw troops in a "careful way that we don't see a complete collapse into violence."

"Moving the ship of state is a slow process," Obama said, adding that this particular ship was like a tanker, not a speedboat. "In the end, only time will tell."

Obama made a point of distancing himself from the unilateralist outlook of the previous Bush administration. He also frequently referred to his full name - Barack Hussein Obama - and emphasized his international background and the fact that he has Muslim relatives.

Tellingly, those are both facts he downplayed during his presidential campaign.

He said dialogue is needed to solve the world's problems and urged the young people at the meeting to explore different cultures.

"Simple exchanges can break down walls between us. For when people come together and share common experiences, their common humanity is revealed," Obama told the students.

The president said tackling climate change would be "very big, very difficult and very costly," but that his administration was committed to do so.

He ended the town hall meeting with a message similar to that of his presidential campaign saying that he believed in the prospect of peace in the Middle East, of success in Iraq and in the battle against al-Qaeda.

"If we don't try. If we don't reach high then we won't make any progress," Obama said.

Earlier on Tuesday Obama toured two of Istanbul's most popular tourist and religious sites: the Hagia Sophia, a former basilica turned mosque that is now a museum, and the nearby Blue Mosque.

In the morning, the president also held a meeting with Armenian Orthodox Archbishop Aran Stesyan, Chief Rabbi of Istanbul Isak Haleva, Grand Mufti of Istanbul Mustafa Cagrici and Syrian Orthodox Archbishop Yusuf Cetin before holding a private meeting with Greek Orthodox Patriach Bartholomew I.

On Monday, Obama addressed the Turkish parliament in Ankara with a speech designed to heal rifts between the United States and Turkey, as well as the Islamic world, caused by the US-led invasion of Iraq.

On Monday, he stressed the need for cooperation - not just force - to stop Islamic extremists. He also emphasized that the United States supports Turkey's bid to join the European Union, as well as recent efforts between Turkey and Armenia to normalize relations.

The visit fulfills Obama's promise to visit a Muslim country in the first 100 days of the new administration.

Obama was scheduled to leave Istanbul for Washington Tuesday afternoon.