United States Secretary of State John Kerry said Iran must reduce its capacity to make nuclear fuel if it wants to secure a long-term agreement with six world powers and end sanctions before the July 20 deadline, according to The Associated Press.
For its part, Tehran suggested that an extension of talks beyond a July 20 deadline was likely, the AP reported.
Iran and the six nations are trying to bridge differences in negotiating positions over a deal intended to end a decade-long dispute over Tehran's nuclear program, according to the AP.
The West fears the program may be aimed at developing a nuclear weapons capability but Iran says it is for peaceful purposes, the AP reported.
"We have made it crystal clear that the 19,000 (nuclear centrifuges) that are currently part of their program is too many," Kerry told reporters after three days of talks with Iranian Foreign Minister Mohammad Javad Zarif, according to the AP.
The proposal was consistent with a speech by Iran's Supreme Leader, Ayatollah Ali Khamenei, which diplomats said had limited the Iranian delegation's ability to make concessions and could make it difficult for Tehran to reach a deal, according to the AP.
Kerry said the talks, involving the United States, Britain, France, Germany, Russia and China as well as Iran, had made tangible progress on key issues but gaps remained, the AP reported.
"It is clear we still have more work to do and our team will continue to work very hard to try to reach a comprehensive agreement that resolves the international community's concern," Kerry said, according to the AP. "There are more issues to work through and more provisions to nail down to ensure that Iran's program can always remain exclusively peaceful."
Zarif echoed Kerry's remarks, saying that although he had had good talks with the U.S. diplomat, serious differences remained between the two sides, the AP reported. He suggested prolonging the talks past July 20 was likely since "I see an inclination on the part of our negotiating partners that they believe more time may be useful and necessary."
