The US State Department said - Monday - that an agreement to return to the Iran nuclear agreement is neither imminent nor certain, and that Washington is preparing for scenarios of joint return or not to return to the full implementation of the agreement.

State Department spokesman Ned Price said Washington was prepared to take "difficult decisions" to restore restrictions on Iran's nuclear program.

And Price had said in previous statements, “We are close to a possible agreement, but we have not yet reached it,” after statements by an informed source last Wednesday that the United States is considering removing the Iranian Revolutionary Guard from the blacklist of “foreign terrorist organizations,” in a move that comes amid efforts to revive 2015 agreement.

This was followed by statements by Iranian Foreign Minister Hossein Amir Abdollahian, in which he said that two "issues" remained stuck with the United States before reaching an understanding to revive the agreement on the nuclear program in the currently stalled Vienna negotiations.

Meanwhile, the Russian TASS news agency quoted Russia's ambassador to Iran Levan Dzagaryan as saying on Monday that he hopes to resume efforts to revive the Iranian nuclear deal after the Nowruz holiday.

Efforts to conclude a new deal have yet to be completed after a last-minute request from Russia forced world powers to pause talks, although nearly most of the text of the agreement was agreed upon.

Iran and the major powers have been engaged in talks over the past 11 months in Vienna to revive the 2015 nuclear deal that curbed its nuclear program in return for the lifting of sanctions.