U.S. Secretary of State John Kerry is meeting with Iranian Foreign Minister Minister Mohammad Javad Zarif in Vienna Friday on key disputes that have prevented nuclear negotiators from meeting a June 30 deadline.
The discussions follow IAEA Director General Yukiya Amano’s trip to Tehran where he met with President Hassan Rouhani and Secretary of the Supreme National Security Council Ali Shamkhani.
The discussions were aimed at moving forward on sticking points regarding IAEA monitoring and verification of Iran's nuclear sites under an agreemnt.
"I believe that both sides have a better understanding on some ways forward, though more work will be needed," Amano told reporters.
No sign of breakthrough
Meanwhile, Iranian nuclear talks prepared to enter a second week, with no visible sign of a breakthrough on the disputes.
Negotiators from Iran and six world powers have given themselves a Tuesday deadline (July 7) to come up with a comprehensive deal to lift international sanctions in exchange for Tehran scaling back its nuclear program.
The discussions in Vienna have been described by officials as slow-moving but headed in the right direction, and it is widely believed that a deal eventually will be reached during the current round of negotiations.
"I don't think we're at any kind of a breakthrough moment yet," said British Foreign Secretary Philip Hammond on Thursday. "We will continue to do whatever we need to do to keep the momentum."
Senior diplomats from the United States, United Kingdom, China, France, Russia and Germany have joined their Iranian counterparts for the high-level talks, which were extended for a week after negotiators missed a June 30 deadline.
"Things have advanced, but we have not yet reached the end," said French Foreign Minister Laurent Fabius late Thursday.
Russian Deputy Foreign Minister Sergei Ryabkov said over 90 percent of the deal has been agreed to and that the remaining problems could be worked out within days.
Iranian negotiators have taken a hard stance, at least publicly, on several key unresolved issues.
For instance, Iran says it wants the sanctions to be lifted immediately and permanently, with no ability to automatically "snap back" into effect if the terms of the deal are violated.
There is also a disagreement over what access international inspectors would have to Iran's nuclear and military facilities, as well as sensitive documents related to the atomic program.
IAEA protocols
A senior Iranian official told reporters the issue could be resolved by Tehran agreeing to the International Atomic Energy Agency's rules known as the "Additional Protocol."
But U.S. officials view the IAEA protocols as insufficient because they would allow Iran to deny access to certain sites.
IAEA chief Yukiya Amano was in Tehran Thursday for separate talks aimed at addressing concerns over past Iranian nuclear activity.
Iranian officials were quoted in state media as saying the talks were "constructive," but the IAEA did not comment on the discussions.
The U.S. and its allies for years have suspected Iran's nuclear program is aimed at building a nuclear weapon. Iran denies this, saying the program only has peaceful, civilian purposes.