US State Department spokesperson Ned Price said on Tuesday that the onus is now on Iran on whether it is willing to enter into a mutual return to compliance with the 2015 nuclear deal with world powers.
A return to the deal remained uncertain and was not imminent, Price said, despite optimism in recent weeks that indirect talks between Iran and the United States could soon produce an agreement.
"We are close to a possible deal, but we're not there yet," Price said on March 16. "We do think the remaining issues can be bridged."
US officials said they thought Tehran would reach an agreement after Sunday's celebration of Nowruz.
But that tone suddenly changed the following day.
"I want to be clear that an agreement is neither imminent nor is it certain," Price said Monday.
And on Tuesday, while refusing to say the talks had reached an impasse, Price said the United States had contingency plans if a deal could not be reached and Iran's alleged plans to develop nuclear weapons were not halted.
"The onus is on Tehran to make decisions that it might consider difficult," he told reporters.
"In fact we are preparing equally for scenarios with and without a mutual return to full implementation of the JCPOA," he said, referring to the formal name of the 2015 deal, the Joint Comprehensive Plan of Action.
The administration of president Donald Trump unilaterally abrogated the six-party JCPOA in 2018, accusing Tehran of violating its terms and branding it a weak deal.
Experts said Iran had mostly stuck to the terms, but months after the US pullout, Tehran began ramping up its nuclear program with activities that would enhance its ability to build a nuclear weapon.
Last April, three months after he took office, President Joe Biden started new negotiations to revive the 2015 agreement, promising an easing of punishing sanctions in exchange for restoring JCPOA controls.
But the talks have proceeded with the knowledge that Tehran has already moved much closer to nuclear weapons "breakout," which would render the JCPOA moot.
