National security adviser Jake Sullivan said Friday that talks for Iran to rejoin the 2015 nuclear deal are “not going well,” offering a blunt assessment as European negotiators warn time is running out on negotiations.

“It’s not going well in the sense that we do not yet have a pathway back into the [Joint Comprehensive Plan of Action or JCPOA],” Sullivan said at an event hosted by the Council on Foreign Relations.

Sullivan said the past few days have brought “some progress” at the negotiating table, but Iran has “raced” its nuclear program since the U.S. pulled out of the deal in 2018 under then-President Trump. 

The deal called for Iran to dismantle much of its nuclear program and open facilities to inspections in exchange for sanctions relief. But Tehran largely stopped complying with the terms of the deal in 2019 after the U.S. left.

“Getting that program back into a box through a return to mutual compliance with the JCPOA has proven more difficult through the course of this year than we would have liked to see,” Sullivan said. “And we are paying the wages of the disastrous decision to leave the deal back in 2018.” 

Talks for Tehran to rejoin the Obama-era nuclear pact restarted in late November after they were halted in June, following the election of Iranian President Ebrahim Raisi, a hard-line critic of the West. The U.S. is not directly participating in the negotiations since it is not a party to the deal.

Negotiators from France, Germany and the United Kingdom — the “E3” countries that are part of the deal — told The Hill in an email that “technical progress” had been made within the past 24 hours.

Iran’s top negotiator, Ali Bagheri Kani, announced on Twitter Thursday that “good progress” had been made, and that talks would continue after a “break of a few days.”

Bagheri Kani decided to go back to Iran for “consultations” on Friday, the E3 negotiators said, adding that the decision brings a "disappointing pause" in negotiations. 

“We hope that Iran is in a position to resume the talks quickly, and to engage constructively so that talks can move at a faster pace,” the negotiators said.

“As we have said, there are weeks not months before the JCPOA’s core non-proliferation benefits are lost. We are rapidly reaching the end of the road for this negotiation,” they continued. “Iran’s nuclear programme is now more advanced than it has ever been. It is critical that Iran avoids further escalatory steps.”