"We knew it would have been difficult, challenging, and sometimes hard," said Federica Mogherini, the European Union's foreign policy chief. Negotiations, she said, will continue for the next couple of days despite hitting some "tense" moments.
As the latest target date arrived for a deal setting a decade of restrictions on Iran's nuclear program, U.S. Secretary of State John Kerry, Iranian Foreign Minister Mohammad Javad Zarif and other top diplomats huddled in Vienna in search of a breakthrough.