WASHINGTON, July 29 (Xinhua) -- The chief U.S. negotiator in Iran nuclear talks on Tuesday cited "significant and steady" progress over the past six months, but would not say whether the negotiations would be further extended.
"I cannot tell you today that our diplomacy will succeed because I am not sure that it will," Wendy Sherman, undersecretary of state for political affairs, told senators at a hearing.
"I can tell you that the past six months, we have made significant and steady progress," she said. "We've exchanged ideas, narrowed gaps on key issues, and identified areas where more hard work is required."
Under an interim deal reached between Iran and Britain, France, the United States, Russia, China and Germany that went into effect on Jan. 20, Iran would suspend some sensitive nuclear activities in exchange for a limited sanction relief, and the two sides will negotiate over a comprehensive deal within six months.
Iran and the six world powers agreed on July 19 to extend their talks until Nov. 24, as disagreements remained over Tehran's uranium enrichment capacity, its Arak heavy water reactor and the sanctions following a 16-day negotiations in Vienna.
"We will use this time to continue working towards that comprehensive plan for ensuring that Iran does not obtain a nuclear weapon, and that its program is exclusively peaceful," Sherman said at the Senate Committee on Foreign Relations hearing.
But she declined to say whether the talks would be extended again beyond Nov. 24.
"I have learned in negotiations that it is very difficult to say what will happen at the end of any given period of time," said the lead U.S. negotiator, adding "Our intent is absolutely to end this on Nov. 24 in one direction or another."
Asked about the duration of a potential comprehensive deal with Iran, she said: "We believe that the duration of this should be at least double-digits, and we believe that it should be for quite a long time."
Many U.S. lawmakers, suspicious of Iran's intentions, have reservations about the current talks with the Islamic republic.