Germany, France and the United Kingdom are preparing to formally trigger the reimposition of United Nations sanctions on Iran, three European officials told CNN on Wednesday.

The so-called “snapback” mechanism, built into the terms of the 2015 Iran nuclear deal, could be initiated as early as Thursday.

The 30-day process to fully restore sanctions would give a small window for diplomacy, European leaders hope Tehran will use that time to reengage with the international community in serious talks, open its facilities to inspectors and do more to comply with its nuclear obligations.

Iran, however, has threatened serious consequences if sanctions are reimposed, which could further destabilize a region already reeling from recent conflict.

The snapback mechanism is part of the 2015 Joint Comprehensive Plan of Action (JCPOA) which allowed members to reimpose UN sanctions on Iran if they believe Tehran is in violation of the deal. That authority expires in October.

Iran has since expanded its nuclear program far beyond the JCPOA limits after former President Donald Trump unilaterally withdrew from the deal in 2018. Tehran maintains that its nuclear program is for peaceful energy purposes, but inspectors and analysts say its capabilities are getting dangerously close to weapons-grade production.

“This is a very good thing because going back to the original JCPOA, according to the Iranian behavior today, would be almost impossible,” International Atomic Energy Agency (IAEA) head Rafael Grossi said Wednesday.

U.S. Secretary of State Marco Rubio said Wednesday he had coordinated with his European counterparts this week as they moved to trigger snapback and described it as “a very powerful piece of leverage on the Iranian regime.”

Inspectors return under tense climate

Inspectors from the International Atomic Energy Agency (IAEA) are back at the Bushehr nuclear power plant in Iran despite the Iranian parliament passing legislation to cease cooperation with international inspectors, head of the agency Rafael Grossi confirmed on Wednesday.

“We are at Bushehr,” he told reporters in Washington on Wednesday. “Today we are inspecting Bushehr. We are continuing the conversation so that we can go to all places, including the facilities that have been attacked.”

The IAEA’s safeguards come from the Nuclear Non-Proliferation Treaty (NPT) which Iran has not withdrawn from. According to the parliament legislation, withdrawing from the NPT is one of Iran’s options if UN sanctions are reimposed.

Iranian Foreign Minister Abbas Araghchi said on Wednesday that inspectors were in Bushehr to monitor the replacement of fuel after a decision by the country’s Supreme National Security Council. But he denied that Iran had made any decision to give “new cooperation” to the agency.

Damage at the Iran’s Isfahan Nuclear Technology Research Center, at the entrance of the conversion and storage facility, after Israeli strikes on June 14-15, 2023. Photo by CommercialSat/MetaNonTheia/Eyevine/UIG via Getty Images

Fallout from recent Israel-Iran conflict

Tensions sharply rose after Israel struck Iranian nuclear facilities in June, which resulted in a 12-day conflict. Iran retaliated with attacks on Israeli cities and US forces joined in the last three days of the conflict, striking three Iranian sites.

In July, the IAEA withdrew its inspectors, saying the war made it impossible for inspectors to monitor the nuclear facilities. Satellite imagery later showed entrances to Iran’s Isfahan Nuclear Technology Research Center appeared to have been damaged in Israeli strikes.

Iran also accused the agency of helping Israel justify its strikes on nuclear facilities by publicizing non-compliance with IAEA safeguard rules.

Iranian divisions over reopening facilities

The decision by the Iranian parliament to allow the IAEA inspectors to visit the Bushehr nuclear plant but not others has been criticized domestically. Parliamentary member Kamran Ghazanfari lashed out at comments made by Speaker Mohammad Bagher Ghalibaf that Iran’s parliament was only suspending the IAEA’s ability to visit some facilities, including Natanz.

Ghazanfari said the limited inspections are an “explicit violation” of the laws which passed in parliament to suspend all cooperation with the agency.

Iran’s parliament had passed the legislation after the June conflict, which lawmakers said was necessary to protect the country against foreign aggression and biased IAEA reports.

Limited time left for diplomacy

European negotiators met with Iranian counterparts in Geneva on Tuesday in an effort to prevent the imposition of sanctions, but sources close to the meeting say little progress was made.

Ahead of the Israel-Iran conflict, U.S. envoy Steve Witkoff had been working on diplomatic talks with Iran to create a new nuclear deal, but those efforts have also ended with the outbreak of hostilities.

Grossi is hopeful that the next month could bring about some de-escalation. “Don’t forget that there is still time, even if there is the triggering thing, there is a month, and many things could happen,” he said.

In the coming weeks Iran will face growing pressure from the West but also from its own political system as to whether to allow international access to its nuclear facilities. With the snapback mechanism to reimpose UN sanctions expiring soon, the coming weeks could see whether diplomacy survives or if sanctions and confrontation will define the next chapter in Iran’s nuclear saga.