Inside Iran's nuclear talks

Iran's Foreign Minister Mohammad Javad Zarif (C on left) and head of the Atomic Energy Organization of Iran Ali Akbar Salehi (C on right) talk outside with aides after a morning negotiation session with U.S. Secretary of State John Kerry over Iran's nuclear program in Lausanne March 19, 2015. REUTERS/Brian Snyder

U.S. Secretary of State John Kerry and staff look at a tablet following talks at the Swiss Federal Institute of Technology in Lausanne (Ecole Polytechnique Federale De Lausanne) April 2, 2015. REUTERS/Brendan Smialowski/Pool

Iran's Foreign Minister Javad Zarif gestures as he speaks during a news conference at the Swiss Federal Institute of Technology in Lausanne on April 2, 2015, after talks finished. REUTERS/Brendan Smialowski/Pool

U.S. Secretary of State John Kerry (L) cycles past the Olympic Museum in Lausanne, March 16, 2015. REUTERS/Denis Balibouse

A late night view of the Beau Rivage Palace Hotel during talks in Lausanne, April 1, 2015. REUTERS/Brendan Smialowski/Pool

Iranian Foreign Minister Javad Zarif (center L), U.S. Secretary of State John Kerry (center R) and European Union High Representative Federica Mogherini (2nd R) arrive to deliver statements after talks at the Swiss Federal Institute of Technology in Lausanne April 2, 2015. REUTERS/Brendan Smialowski/Pool

U.S. Secretary of State John Kerry looks out of his room at the Beau Rivage Palace Hotel during a break during talks in Lausanne April 1, 2015. REUTERS/Ruben Sprich

The head of Iranian Atomic Energy Organization Ali Akbar Salehi (R) looks over papers before meetings at the Beau Rivage Palace Hotel March 28, 2015 in Lausanne. REUTERS/Brendan Smialowski/Pool

Iranian Foreign Minister Javad Zarif waits to make a statement next to U.S. Secretary of State John Kerry, following talks at the Swiss Federal Institute of Technology in Lausanne April 2, 2015. REUTERS/Brendan Smialowski/Pool

U.S. Secretary of State John Kerry sits in a courtyard at the Beau Rivage Palace Hotel during an extended round of talks in Lausanne April 2, 2015. REUTERS/Brendan Smialowski/Pool

U.S. Secretary of State John Kerry (2nd R) speaks with U.S. Secretary of Energy Ernest Moniz speak as Iranian Foreign Minister Javad Zarif (not pictured) reads a statement, following nuclear talks at the Swiss Federal Institute of Technology in Lausanne April 2, 2015. REUTERS/Brendan Smialowski/Pool

A police officer holds back a protester demonstrating against the talks outside the Beau Rivage Palace Hotel in Lausanne April 2, 2015. REUTERS/Ruben Sprich

Iranian Foreign Minister Javad Zarif smiles as he waits for the start of a meeting with P5+1, European Union and Iranian officials at the Beau Rivage Palace Hotel in Lausanne March 30, 2015. REUTERS/Brendan Smialowski/Pool

U.S. Secretary of State John Kerry waits with others before a meeting with P5+1, European Union and Iranian officials at the Beau Rivage Palace Hotel in Lausanne March 30, 2015. REUTERS/Brendan Smialowski/Pool

U.S. Secretary of State John Kerry and U.S. Secretary of Energy Ernest Moniz cross paths during a lunch break in negotiations with Iranian officials on March 27, 2015 in Lausanne. REUTERS/Brendan Smialowski/Pool

Iranian Foreign Minister Javad Zarif talks to members of the media while walking through a courtyard at the Beau Rivage Palace Hotel during an extended round of talks in Lausanne April 1, 2015. REUTERS/Brendan Smialowski/Pool

U.S. Secretary of State John Kerry checks his watch outside the Beau Rivage Palace Hotel in a break during talks in Lausanne April 1, 2015. REUTERS/Ruben Sprich

Russian journalists play a game of giant chess in a courtyard at the Beau Rivage Palace Hotel in Lausanne, April 1, 2015. REUTERS/Brendan Smialowski/Pool

The head of Iranian Atomic Energy Organization Ali Akbar Salehi (R) looks over papers before meetings at the Beau Rivage Palace Hotel March 28, 2015 in Lausanne. REUTERS/Brendan Smialowski/Pool

Reporters sit in a hallway as they wait during negotiations at the Beau Rivage Palace Hotel in Lausanne, March 31, 2015. REUTERS/Brendan Smialowski/Pool

Hamid Baeedinejad (L), an Iranian official, speaks with the press outside the Beau Rivage Palace Hotel in Lausanne March 31, 2015. REUTERS/Brendan Smialowski/Pool

U.S. Secretary of State John Kerry arrives at Geneva International Airport March 26, 2015. REUTERS/Brendan Smialowski/Pool