The ultimate aim, U.S. officials have repeatedly said, is to achieve an agreement that permits Iran to continue to develop an exclusively peaceful nuclear program with commitments from Iran that it will not seek to develop a nuclear weapon. "These goals," Kerry reiterated Tuesday, "are not incompatible. In fact, they are realistic."
Kerry is seeking concrete assurances from Iran regarding the purpose of its nuclear program.
"Over the past few days, I have had lengthy conversations with Foreign Minister Zarif about what Iran is willing to do and what it needs to do to not only assure the community of nations, but to adhere to what the foreign minister himself has said repeatedly are Iran's own limited objectives: not just to declare that they will not obtain a nuclear weapon, but to demonstrate in the actions they take beyond any reasonable doubt that any Iranian nuclear program, now and going forward, is exclusively for peaceful purposes."
Despite the hurdles, Kerry hailed "tangible progress on key issues," stating Tuesday that "we moved on certain things" but offered no specifics.
Kerry announced he was returning to Washington to consult with President Barack Obama.
Meanwhile, negotiations amongst other delegates from the P5+1 countries -- the five permanent members of the U.N. Security Council (the U.K., China, France, Russia, the U.S.) plus Germany -- with Iranian Foreign Minister Javad Zarif and European Union foreign policy chief Catherine Ashton will continue, as they seek to reach a comprehensive agreement by the July 20 deadline.