Iran repeated that it won’t discuss the beleaguered accord with the Biden administration until Washington officially rejoins as a participant and lifts Trump-era sanctions on Iran’s economy.

“Once everybody implements their parts of the obligation there will be talks, and those talks will not be about changing the terms of the agreement, regional issues or missile issues. We’re not going to discuss those,” Iran’s Foreign Minister Mohammad Javad Zarif said in an interview with state-run Press TV.

Any negotiations with the U.S. would have to address the need for a guarantee that Washington won’t quit the deal again, Zarif added. President Donald Trump pulled the U.S. out of the accord that put strict limits on Iran’s nuclear program in exchange for sanctions relief.

In an interview with CBS News on Sunday, U.S. National Security Advisor Jake Sullivan said “it is Iran that is isolated diplomatically now, not the United States, and the ball is in their court.”

He said an offer by President Joe Biden to talk with Iran about how it returns to full compliance with the nuclear accord “still stands” after Tehran rebuffed the overture on Friday. In a sign that diplomatic efforts were making some ground, Sullivan said the two countries are in contact over the release of American nationals held detained by Iran — an issue that will be critical to how the two resolve their wider hostilities.

Iran confirmed it had received messages from the U.S. via the Swiss embassy in Tehran, which represents Washington’s interests in the Islamic Republic, but said there had been no direct contact between the two at all, Foreign Ministry Spokesman Saeed Khatibzadeh said in an interview with state TV.

Iran’s Next Step Raises Specter of War for Top Atomic Lawyer (1)

The lack of any change in either country’s stance increases the likelihood Iran will suspend the so-called Additional Protocol — a voluntary agreement with the United Nations’ International Atomic Energy Agency, which allows for more intrusive and short notice inspections of nuclear and military sites — on Feb. 23.

The head of the IAEA, Rafael Mariano Grossi, is currently in Tehran and has met both Zarif and the country’s top nuclear officials. So far their talks have been “fruitful,” Iran’s envoy to the Vienna-based body, Kazem Gharibabadi, said in a tweet, adding that details of the meetings will be published later on Sunday.

Iran Snubs Biden in Seeking End to Sanctions Before Talks

The Additional Protocol gives monitors cradle-to-grave information about nuclear material and installations in countries adhering to the rules. Inspectors can call snap visits to sites they suspect could harbor undeclared activity.

While the IAEA will still be allowed into Iran, so that it can account for declared nuclear stockpiles, they’ll lose oversight at places like machine shops and mines, where equipment and material is produced to make enriched uranium. Zarif said the restrictions on nuclear inspections will also mean the UN body will no longer have access to camera footage of its nuclear sites.

The nuclear deal was agreed by Iran, the U.S., the EU, Russia and China in July 2015 to address the West’s concerns that Iran may be trying to develop nuclear weapons. Iran has always maintained that it’s atomic activities are for civilian purposes only and that it’s banned nuclear weapons.

When former President Trump unilaterally exited the deal, he violated its terms by reimposing and expanding a severe sanctions regime on Iran’s economy. Iran started to ramp-up its nuclear activities in retaliation. The crisis almost triggered a war between the two countries.

Biden was effectively continuing Trump’s “maximum pressure” policy by choosing to maintain sanctions and doing nothing to allow Iran access to at least $10 billion trapped in overseas accounts because of the U.S. penalties, Zarif said.

Iran would return to full compliance with the original terms of the deal “the minute” the U.S. officially rejoins, Zarif said, adding that Iran will continue to increase its stockpile of 20% enriched uranium as long as Washington isn’t part of the deal.