U.S. Secretary of State John Kerry heads to Geneva Friday for talks on Iran's nuclear program, amid signs a deal is within reach.
The State Department says it hopes Kerry's presence will "help narrow differences" in the negotiations between Iran and six world powers.
Both sides reported progress Thursday on a deal requiring Iran to scale back its nuclear program in exchange for sanctions relief.
Iranian Foreign Minister Mohammed Javad Zarif told cnn he believes an agreement can be reached before the close of negotiations Friday.
Iran is seeking an end to sanctions that have devastated its economy, while the six nations want assurances Iran is not building nuclear bombs.
In Washington, President Barack Obama said the deal being discussed would offer "modest relief" from the sanctions, but that most would stay in place.