At last round of Iran talks, pressure was palpable

WASHINGTON - Food boxes strewn across the floor. An espresso machine buzzing constantly in the background. Physicists catnapping, their heads on tables.

That was the scene at one of Switzerland's finest hotels, where room service kept the deliveries coming as U.S. diplomats worked feverishly to achieve a landmark nuclear deal with Iran.

If the pressure wasn't enough, Secretary of State John Kerry kept popping into the room to pull individuals aside or tell them to accelerate their efforts, according to U.S. officials. They spoke on condition of anonymity because they were not authorized to talk publicly about behind-the-scenes interactions.

From the start of March through Thursday's breakthrough, Kerry spent 19 days in the Swiss cities of Geneva, Lausanne, and Montreux negotiating with the Iranians.

For much of that time, the Europeans, Chinese, and Russians stayed away or sent lower-level officials. Kerry and Iranian Foreign Minister Mohammad Javad Zarif spent more than 10 hours together in one-on-one sessions.

The last round of discussions began March 26 with the goal of wrapping up work within five days. The U.S. would extend the talks by two days, regularly preparing the plane for departure so the Iranians would not think the talks were open-ended.

Journalists were told three times to drop off their bags, only to be instructed to extend their hotel bookings. Plane crews kept bumping up against mandatory rest periods after 15 hours on standby.

Kerry tried to keep a clear head, taking to his bicycle during the limited down time he had. Of his three rides, two were interrupted when President Obama called for an update. In those instances, Kerry had to rush back to Lausanne's 19th-century Beau-Rivage Palace to dial into secure calls.

When talk of physics got too nitty-gritty, Kerry and Zarif sent top scientists out of the room to discuss the matter fully. Energy Secretary Ernest Moniz and Iranian atomic energy chief Ali Akbar Salehi, who studied at MIT at the same time, would meet one on one and then report back.

When Kerry needed calculations or tweaks, officials described him putting his team to work and sometimes popping in to let them know they needed to move more quickly. Kerry also got involved in details as granular as travel plans for the other foreign ministers and helping with scheduling conflicts. After Russian Foreign Minister Sergey Lavrov left, Kerry persuaded him to come back.

The critical meeting with the Iranians lasted nine hours between Wednesday night and Thursday morning. Emotions at times ran high as sleep deprivation kicked in.

Not everything went smoothly. U.S. nuclear experts at one point scribbled classified information on the whiteboard usied to explore ideas. But someone used a permanent marker by mistake. It took 20 minutes to scrub off the information, officials said.