The White House is worried Iran could develop a nuclear weapon in weeks, press secretary Jen Psaki said on Tuesday.
"Yes it definitely worries us," Psaki said, according to Reuters.
She added that the time needed for Iran to produce a nuclear weapon is down from about a year.
Her comments came hours after Secretary of State Antony Blinken said that Iran has accelerated its nuclear program.
Iran has gradually scaled back its compliance with the 2015 deal, in response to former US President Donald Trump’s withdrawal from the agreement in May of 2018, but has held several rounds of indirect talks with the US on a return to the agreement.
Negotiations nearly reached completion last month before Moscow demanded that its trade with Iran be exempted from Western sanctions over Ukraine, throwing the process into disarray.
Days later, Moscow said it had received the necessary guarantees.
On Monday, Iran called for a new meeting "as soon as possible" in the nuclear talks.
"It is appropriate that a face-to-face meeting is held as soon as possible," foreign ministry spokesman Saeed Khatibzadeh told his weekly press conference, according to the AFP news agency.
"It is not yet decided where and when to have this meeting and at what level it should be held, but it is on the agenda," he added.
Meanwhile, Israel Hayom reported on Tuesday that Israel's political echelon estimates that the chance of the US signing an agreement with Iran is dropping "at an increasing rate".
Two sources in the political echelon told the newspaper that as of now, it seems that the chance of an agreement is low and possibly even nil.
Those sources emphasized that there still may be a surprising turn of events, at the end of which an agreement is signed, but according to one of them, "the chance that the sides will sign an agreement in the foreseeable future is moving further away, at an exponential rate."