By CNN Chief National Security Correspondent Jim Sciutto
In a possible sign of a breakthrough, several top diplomats - including those from the United States, Russia, the European Union and Iran - met in or headed to Geneva on Friday for talks on Tehran's nuclear program.
U.S. State Department spokeswoman Jen Psaki said that Secretary of State John Kerry would depart for the Swiss city "later today with the goal of continuing to help narrow the differences and move closer to an agreement." The American diplomat is expected to land there around 7:45 a.m. Saturday (1:45 a.m. ET), according to a Western official.