By Associated Press, Jun. 29, 2015

VIENNA (AP) -- World powers and Iran prepared to move past Tuesday's deadline for a comprehensive nuclear agreement, with officials suggesting significant backtracking by Tehran's negotiators that may need several more days of discussions to resolve.

On a day that served as an early intermission in the negotiation, U.S. Secretary of State John Kerry met the head of the U.N. nuclear agency in Vienna while Iranian Foreign Minister Mohammad Javad Zarif received his latest guidance from leaders in Tehran. Zarif was scheduled to return to the talks Tuesday, followed by the arrival of Russia's top diplomat.

Monday was originally envisioned as the penultimate day of a 20-month process to assure the world Iran cannot produce nuclear weapons and provide the Iranian people a path of out of years of international isolation. But officials said over the weekend they were nowhere near a final accord, and Zarif flew back to his capital for further consultations.