Germany, France and the United Kingdom are poised to activate the reimposition of UN sanctions on Iran, three European officials told CNN on Wednesday. The so-called “snapback” provision is part of the 2015 Iran nuclear deal and could be triggered as soon as Thursday.

The process to restore UN sanctions takes 30 days. European officials expressed hope that Tehran would use that time to reengage in meaningful negotiations, open its facilities to international inspectors, and take steps toward coming back into compliance with its nuclear obligations.

Iran, on the other hand, has threatened strong retaliation if sanctions are reinstated. The potential consequences include further volatility in the Middle East, which is still reeling from last month’s conflict.

Snapback Mechanism Expiring Soon

Snapback is a provision under the 2015 Joint Comprehensive Plan of Action (JCPOA) that allows members of the agreement to reinstate UN sanctions if Iran violates its terms. The provision is set to expire in October, and European countries are racing the clock to take advantage.

Iran has expanded its nuclear program well beyond the limits of the JCPOA since the United States withdrew from the agreement under former President Donald Trump. Tehran maintains its program is peaceful, but nuclear inspectors and analysts are warning that its enrichment capabilities are getting close to weapons-grade levels.

“Going back to the original JCPOA would be almost impossible,” Rafael Grossi, the head of the International Atomic Energy Agency (IAEA), said Wednesday.

U.S. Secretary of State Marco Rubio, who met with his European counterparts this week to coordinate the snapback, called it “a very powerful piece of leverage on the Iranian regime.”

Inspectors Returned to Facilities

Iranian lawmakers this week passed legislation that would end cooperation with international nuclear inspectors. But inspectors from the IAEA have recently been given access to some of Iran’s nuclear facilities. Grossi confirmed that teams were at the Bushehr nuclear power plant on Wednesday.

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

The IAEA is allowed to carry out safeguards of Iran’s nuclear facilities under the Nuclear Non-Proliferation Treaty (NPT). Iran is a signatory to the treaty, but has reportedly made withdrawal from the NPT one of the potential consequences if sanctions are reimposed.

Iranian Foreign Minister Abbas Araghchi said the IAEA teams were present at Bushehr to monitor the replacement of fuel rods. He later denied that Iran has agreed to any “new cooperation” with the IAEA.

Conflict Between Israel and Iran Escalated Quickly

Tensions between Israel and Iran had been building for months, but they reached a boiling point when Israel struck Iran’s nuclear facilities in June. This set off a 12-day war, during which Iranian military groups launched missiles at Israeli cities. The United States later joined in the attacks, striking three Iranian sites over three days.

In July, the IAEA withdrew its inspectors from Iranian nuclear facilities, saying the conflict had created a condition where they could no longer guarantee their safety. Satellite images later revealed that several entrances at Iran’s Isfahan Nuclear Technology Research Center had been damaged during the fighting.

Tehran later accused the IAEA of helping Israel build a case for its attacks by publicizing instances where Iran had not been in compliance with the agency’s safeguard rules.

The decision to allow IAEA inspectors to return to some facilities has sparked criticism at home. Parliamentary member Kamran Ghazanfari attacked Speaker Mohammad Bagher Ghalibaf for appearing to support limited IAEA inspections, saying they violated laws passed by the parliament that suspended cooperation with the agency.

Iran’s parliament passed a law after the conflict ending cooperation with the IAEA, a move that Tehran portrayed as a response to foreign aggression and the IAEA’s “biased” coverage of Iran’s non-compliance with safeguard provisions.

Negotiators Tried to Keep Dialogue Alive

European negotiators met with Iranian officials in Geneva on Tuesday, hoping to find a last-minute solution to prevent the reimposition of sanctions. But sources told CNN little progress was made.

Prior to the outbreak of fighting, U.S. envoy Steve Witkoff had been engaged in talks with Iran aimed at reaching a new nuclear agreement. They have since ground to a halt.

Grossi, who met with Iran’s nuclear chief in Tehran this week, was hopeful that the coming month could see 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.

For now, Tehran faces pressure both from Western governments and its own domestic political system. With the snapback mechanism’s expiration date approaching, the coming weeks will determine whether diplomacy can take hold—or whether sanctions and confrontation will be the story of Iran’s nuclear program.