U.S. President Barack Obama told the United Nations on Tuesday that a “different relationship” with Iran is possible. Two days ahead of a meeting between U.S. Secretary of State John Kerry and Iranian Foreign Minister Mohammad Javad Zarif -- the highest-level meeting between the two governments since the Islamic Revolution of 1979 -- Obama told the General Assembly that he will seek a diplomatic resolution of the issue of Iran’s nuclear program.

"I don't believe this difficult history” between the two countries “can be overcome overnight," Obama said. "The suspicions run too deep. But I do believe that if we can resolve the issue of Iran's nuclear program, that can serve as a major step down a long road towards a different relationship, one based on mutual interests and mutual respect."

Iran’s new president, Hassan Rouhani, who has taken a conciliatory tone towards the U.S. and the West since his election in June, was not in the room while Obama spoke, according to Iranian delegates who spoke to the Jerusalem Post. Rumors of a possible meeting between Obama and Rouhani have been swirling for days. Rouhani’s speech to the assembly is scheduled for later Tuesday.

The other main push in Obama’s speech was on Syria. The president called on the U.N. Security Council to pass a resolution that will force the Syrian government to respect an agreement to give up chemical weapons. "There must be a strong Security Council resolution to verify that the Assad regime is keeping its commitments," Obama said. "There must be consequences if they fail to do so."

Obama also called on Iran, as well as Russia, to realize that propping up dictator Bashar Assad in the Syrian civil war goes against their own interest in seeing the country remain stable. In a clear dig at Russian President Vladimir Putin, who had criticized "American exceptionalism" in an opinion piece published by The New York Times earlier this month, Obama said "some may disagree, but I believe America is exceptional" because it has historically defended not only its own national interests but also "the interests of all."

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