U.S. Secretary of State John Kerry and Iranian Foreign Minister Mohamad Javad Zarif sit down for more talks in Vienna, on Wednesday, a day after Iran nuclear negotiators extended their deadline for an agreement to July 7.
Their talks come a day after both President Barack Obama and Iranian President Hassan Rouhani commented on the negotiations underway in Vienna.
Obama said the U.S. would "walk away" from a possible nuclear deal with Iran if he is not convinced it would block Tehran's path to building a nuclear weapon.
Rouhani said Iran would resume suspended atomic activity if Western powers broke promises made in an agreement.
Iran and the five permanent members of the U.N. Security Council and Germany, the so-called P5 + 1, are trying to come up with a plan that would restrict Iran’s ability to make nuclear weapons while providing the country with sanctions relief.
WATCH: Pam Dockins reports from Vienna, Austria
An Iran nuclear deal would be “following the Lausanne framework fairly closely,” said analyst Richard Nephew of the Center on Global Energy Policy. He referred to the framework agreement that Iran nuclear negotiators reached in Switzerland in early April.
A deal would involve reductions in the “installed and operating centrifuges, it will involve a reduction of the amount of enriched uranium in the country which will have a positive impact on breakout and it will involve a modification of the Arak reactor – basically closing the path to the plutonium weapon,” he said.
On Tuesday, the original deadline for an agreement, the U.S. State Department said negotiators decided to extend until July 7 measures under the interim agreement to "allow more time" for talks on Iran's nuclear program to reach a long-term solution.
Word of the extension came as U.S. negotiators held a series of talks with Zarif as well as a Russian delegation led by Foreign Minister Sergei Lavrov.
Rouhani, Amano meeting
Meanwhile, the head of the U.N.'s nuclear agency Yukiya Amano will meet with Iranian President Rouhani in Tehran on Thursday.
"Discussions are expected to address ongoing cooperation between the IAEA and the Islamic Republic of Iran under the Framework for Cooperation, and how to accelerate the resolution of all outstanding issues related to Iran’s nuclear program, including clarification of possible military dimensions," an International Atomic Energy Agency statement said.
Iranian leaders have publicly declared in recent weeks that inspectors would not be allowed to access military sites or interview scientists. Inspections and the pace at which sanctions against Iran are lifted remain two of the key sticking points between Iranian negotiators and those from the United States, Britain, China, France, Russia and Germany.