On Wednesday, White House spokeswoman Jane Saki described the ongoing talks with Iran regarding re-accession to the 2015 nuclear deal as a constructive early step, but would not provide a timetable for any decisions.
The United States and Iran are holding indirect talks this week in Vienna about returning to the deal.
The meetings of the Joint Working Committee for the nuclear agreement under the auspices of the European Union began in Vienna, with the participation of the United States for the first time since the arrival of President Joe Biden's administration to the White House.
The meeting was held at the level of deputy foreign ministers of Russia, China, France, Britain, Germany, and Iran, in addition to the United States.
On the agenda was the return of the United States to the nuclear agreement, the lifting of sanctions on Iran, and its retreat from the measures it had taken to reduce its nuclear commitments.
In Tehran, Iranian government spokesman Ali Rabiei said, in a press briefing yesterday morning, that his country had received several proposals on lifting US sanctions through the "4 + 1" group (China, Russia, Britain, France and Germany).
Rabiei stressed the need for Washington to return to the nuclear agreement before any proposal is put forward to negotiate with Tehran, and he stressed that his country is ready to return to all its nuclear commitments if the United States lifted all sanctions, and at the same time ruled out any form of negotiation between the Iranian and American delegations in Vienna.
The Iranian spokesman said that the position of the US envoy on the Iranian file, Robert Malley, who believes that sanctions should be lifted, is "positive for reforming the diplomatic track."
Meanwhile, 3 diplomatic sources said that talks scheduled to be held between the International Atomic Energy Agency of the United Nations and Iran had been postponed to obtain answers from Tehran regarding finding "unjustified" traces of uranium in some sites.
This limits the chances of achieving progress in rapprochement with the West or threatens to undermine the steps that have been taken in this regard.
"The start date in April has been postponed for several weeks. It may be at least two weeks," a European diplomatic source said, adding that the reason for the delay was technical.
Two other diplomats also said that the start of the talks had been postponed, and one indicated that the IAEA delegation would be led by Massimo Abaro, chief inspector.
When asked about the delay, a spokesman for the International Atomic Energy Agency said, "The date has been confirmed in April."
Iranian officials have not yet responded to requests for comment.