Negotiations aimed at returning the United States and Iran to compliance with the 2015 nuclear deal will resume this weekend, U.S. Deputy Secretary of State Wendy Sherman has said.
The talks, brokered by European diplomats, include indirect contacts between U.S. and Iranian negotiators meeting in Vienna. So far there have been five rounds, with negotiators saying early this month that the talks are heading into their most delicate phase.
"I think there's been a lot of progress made, but out of my own experience, until the last detail is nailed down, and I mean nailed down, we will not know if we have an agreement," Sherman said on June 9 during a virtual event organized by the German Marshall Fund.
Sherman, one of the key U.S. negotiators of the original deal, said another factor complicating the negotiations was the June 18 elections to replace President Hassan Rohani, who promoted the 2015 deal and whose successor is widely expected to be a hard-liner.
Negotiators from Britain, France, and Germany, known as the E3, and the other major powers that struck the deal with Iran have been meeting in working groups in the Austrian capital since early April, with the EU team overseeing indirect talks between Iran and the United States.
The deal, formally known as the Joint Comprehensive Plan of Action (JCPOA), has been on hold since 2018, when then-President Donald Trump pulled Washington out of the pact and reimposed crippling sanctions on Iran's economy.
In response, Tehran steadily has overstepped the limits on its nuclear program spelled out in the deal that are designed to make it harder for the Islamic republic to develop an atomic bomb -- an ambition Tehran denies.
U.S. Secretary of State Antony Blinken sounded pessimistic earlier this week when he told lawmakers that it remains "unclear whether Iran is willing and prepared to do what it needs to do come back into compliance."
U.S. State Department spokesman Ned Price raised a separate issue on June 9, saying that Iran had yet to provide the International Atomic Energy Agency (IAEA) with information the agency needs regarding potential undeclared nuclear material.
Price said the United States is deeply concerned Iran has yet to give the IAEA information about traces of uranium found at several undeclared sites.
Most of activity in question dates to the early 2000s, before the nuclear agreement, and has long been a center of inquiry about Iran's past nuclear program.
Iran Nuclear Negotiations To Resume This Weekend, U.S. Official Says
Delegation members from the parties to the Iran nuclear deal -- Germany, France, Britain, China, Russia and Iran -- attend a meeting at Vienna's Grand Hotel on May 1 as they try to restore the accord.