Iran's President Hassan Rouhani waves as his motorcade leaves Tehran's Mehrabad Airport upon his arrival from New York Saturday, one day after he spoke to President Obama by phone. Atta Kenare /AFP/Getty Images hide caption

itoggle caption Atta Kenare /AFP/Getty Images

Iranian President Hassan Rouhani at the U.N. on Tuesday. Ray Stubblebine /Reuters/Landov hide caption

itoggle caption Ray Stubblebine /Reuters/Landov

Much To Smile About? Iranian President Hasan Rouhani prepares to address the 68th session of the U.N. General Assembly on Tuesday. Frank Franklin II/AP hide caption

itoggle caption Frank Franklin II/AP

President Obama addresses the 68th session of the United Nations General Assembly at the United Nations in New York. Timothy Clary/AFP/Getty Images hide caption

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Iranian President Hassan Rouhani during an interview with NBC — part of a charm offensive ahead of his visit to the U.N. General Assembly. Rouzbeh Jadidoleslam/AP hide caption

itoggle caption Rouzbeh Jadidoleslam/AP

Iranian Foreign Minister Mohammad Javad Zarif speaks during a news conference earlier this month. Ahmad Al-Rubaye/AFP/Getty Images hide caption

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Iranian President Hassan Rouhani talks to NBC — part of a charm offensive ahead of his visit to the U.N. General Assembly in New York next week. Rouzbeh Jadidoleslam/AP hide caption

itoggle caption Rouzbeh Jadidoleslam/AP

Iran's President Hasan Rowhani, who was elected in June, has exchanged lettes with President Obama, the U.S. leader said in an interview that aired Sunday. Here, Rowhani speaks to Iran's Parliament in Tehran. Atta Kenare/AFP/Getty Images hide caption

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A U.S. Navy F/A-18F Super Hornet prepares to launch from the aircraft carrier USS Nimitz earlier this week in the Red Sea. The ship is among U.S. military assets in the region. Nathan R. McDonald /UPI/Landov hide caption

itoggle caption Nathan R. McDonald /UPI/Landov

Syrian refugees stand in line for food at Kawergost refugee camp in Irbil, Iraq, on Aug. 21. The Syrian civil war has already sparked a refugee crisis in the region. Now, many countries are waiting to see the effects of a possible U.S. military strike. Hadi Mizban/AP hide caption

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Russian President Vladimir Putin greets his Syrian counterpart, Bashar Assad, in Moscow on Dec. 19, 2006. Russia --€” along with China and Iran --€” has remained a steadfast ally of Assad amid calls for international intervention in Syria. Mikhail Klimentyev/AP hide caption

itoggle caption Mikhail Klimentyev/AP