WASHINGTON, DC - JANUARY 17: (AFP OUT) U.S. President Barack Obama delivers a statement on the relations between US and Iran, including the release of the US hostages that were held in Iran, in the cabinet room of the White House on January 17, 2016 in Washington, DC. Obama praised the implementation of a completed nuclear agreement with Iran and the return of five American prisoners that the country was holding resulting in a lifting of economic sanctions. (Photo byAude Guerrucci-Pool/Getty Images)
US Secretary of State John Kerry gestures during a press conference at the E3/EU+3 and Iran talks at the International Atomic Energy Agency headquarters in Vienna on January 16, 2016.
The historic nuclear accord between Iran and major powers entered into force as the UN confirmed that Tehran has shrunk its atomic programme and as painful sanctions were lifted on the Islamic republic. / AFP / JOE KLAMAR (Photo credit should read JOE KLAMAR/AFP/Getty Images)
US Secretary of State John Kerry speaks during a press briefing at the State Department in Washington, DC, January 7, 2016. AFP PHOTO / SAUL LOEB / AFP / SAUL LOEB (Photo credit should read SAUL LOEB/AFP/Getty Images)
Robert Ford, a Senior Fellow at the Middle East Institute, speaks during a hearing convened by the House Foreign Affairs Committee in Washington, DC on June 17, 2015, to examine the use of chemical weapons in Syria by the Assad regime. AFP PHOTO/ ANDREW CABALLERO-REYNOLDS (Photo credit should read Andrew Caballero-Reynolds/AFP/Getty Images)
WASHINGTON, DC - JANUARY 20: U.S. President Barack Obama delivers the State of the Union address on January 20, 2015 in the House Chamber of the U.S. Capitol in Washington, DC. Obama was expected to lay out a broad agenda to address income inequality, making it easier for Americans to afford college education, and child care. (Photo by Mandel Ngan-Pool/Getty Images)
Tribal gunmen loyal to the Huthi movement brandish their weapons on March 26, 2015 during a gathering in Sanaa to show support the Shiite Huthi militia and against the Saudi-led intervention in the country. Warplanes from a Saudi-led Arab coalition bombed Huthi rebels in support of Yemen's embattled president, as regional rival Iran warned the intervention was a "dangerous" move. AFP PHOTO / MOHAMMED HUWAIS (Photo credit should read MOHAMMED HUWAIS/AFP/Getty Images)
WASHINGTON, DC - SEPTEMBER 10: U.S. Sen. Dianne Feinstein (D-CA) arrives for a Senate Intelligence Committee closed hearing, on Capitol Hill, September 10, 2013 in Washington, DC. President Barack Obama will address the nation about Syria on Tuesday evening. (Photo by Drew Angerer/Getty Images)
A South Korean man watches a television screen showing North Korean leader Kim Jong-Un's New Year speech, at a railroad station in Seoul on January 1, 2015. North Korean leader Kim Jong-Un said he was open to the "highest-level" talks with South Korea as he called for an improvement in strained cross-border relations. AFP PHOTO / JUNG YEON-JE (Photo credit should read JUNG YEON-JE/AFP/Getty Images)
Hassan Rouhani, Iran's president, speaks during a news conference at the Gas Exporting Countries Forum (GECF) summit in Tehran, Iran, on Monday, Nov. 23, 2015. The talks between Putin, on his first visit to Iran since 2007, and Iran's Supreme Leader Ayatollah Ali Khamenei focused on the situation in Syria, where both Russia and Iran back Syrian President Bashar al-Assad, as well as the wider region. Photographer: Simon Dawson/Bloomberg via Getty Images
United States Secretary of State John Kerry poses with Foreign Affairs Minister of Iran Javad Zarif during a bilateral talk at the United Nations headquarters on September 26, 2015, at the United Nations in New York. AFP PHOTO/Dominick Reuter (Photo credit should read DOMINICK REUTER/AFP/Getty Images)
US Secretary of State John Kerry and State Department Chief of Staff Jon Finer (L) meet with members of the US delegation at the garden of the Palais Coburg hotel where the Iran nuclear talks meetings are being held in Vienna, Austria July 10, 2015. Iran accused major powers on Friday of backtracking on previous pledges and throwing up new "red lines" at nuclear talks, after the deadline to reach an agreement in time to receive expedited scrutiny from the US Congress expired with no deal. AFP PHOTO / POOL / CARLOS BARRIA (Photo credit should read CARLOS BARRIA/AFP/Getty Images)