U.S. Secretary of State Antony Blinken said on January 20 that talks to revive the Iran nuclear deal have reached an "urgent" point following "modest progress" in negotiations in Vienna.
However, Blinken told reporters after meeting with European allies in Berlin that reviving the landmark agreement was still possible.
"My own assessment, talking to all of our colleagues, is that returning to mutual compliance, it remains possible," Blinken said, but warned that time was short.
"There is real urgency and it's really now a matter of weeks, where we determine whether or not we can return to mutual compliance with the agreement," Blinken said.
The 2015 deal, which lifted crippling Western economic sanctions in exchange for curbing Tehran's nuclear ambitions, began to unravel in 2018 after U.S. President Donald Trump unilaterally withdrew and reimposed the sanctions.
That led Iran to later start rolling back its commitments, and restarting some uranium-enrichment activity, pushing the deal, formally known as the Joint Comprehensive Plan of Action (JCPOA), to the verge of complete collapse.
Negotiations to restore the agreement began early last year but were put on hold in June as the Islamic republic held its presidential election, which brought an ultraconservative government led by President Ebrahim Raisi to power.
Talks resumed in late November, and the latest round got under way on December 27.
Along with Iran and the United States, other parties to the deal include Britain, China, France, Germany, and Russia.
German Foreign Minister Annalena Baerbock also said "urgent" progress was necessary, adding that time was running out because "Iran, parallel to the talks, unfortunately continues to turn the spiral of nuclear escalation."
Iran, Baerbock said, had achieved 60-percent uranium enrichment, unprecedented for a state without nuclear weapons.
"There is no plausible explanation for this and Iran is not providing a plausible explanation for this," Baerbock said.
French Foreign Minister Jean-Yves Le Drian also warned after the talks in Berlin that quicker progress was needed.
Le Drian told reporters that "the negotiations cannot go on so slowly" on returning to the JCPOA.
On January 19, U.S. President Joe Biden said it was "not time to give up" on the talks with Iran, insisting "there is some progress being made" in the Vienna discussions.