France, Germany and the U.K. will bring back sanctions on Iran via the U.N. Security Council if a nuclear deal is not reached by the end of August, French Foreign Minister Jean-Noel Barrot warned on Tuesday.

Barrot said that the E3, the European countries party to the 2015 Iran nuclear deal known as the Joint Comprehensive Plan of Action, will trigger the snapback mechanism, reimposing all U.N. sanctions, if a new agreement is not reached.

The Trump administration hopes to reach an agreement with the Islamic Republic to stop any uranium enrichment in Iran after Israeli and American strikes on Iran’s nuclear sites last month, aiming to prevent Tehran from rebuilding its severely damaged nuclear program.

“France and its partners are …  justified in reapplying global embargoes on arms, banks and nuclear equipment that were lifted 10 years ago,” Barrot said on the way to a meeting with EU foreign ministers in Brussels. “Without a firm, tangible and verifiable commitment from Iran, we will do so by the end of August at the latest.” 

The snapback mechanism expires in October and takes 30 days to activate, such that the end of August is the last chance to impose U.N. sanctions that cannot be vetoed by Russia and China, Iran’s allies on the Security Council. Moscow is slated to assume the presidency of the U.N. Security Council in October and could try to obstruct the move if it is not completed before then.

The E3 reached the shared policy in a phone call with Secretary of State Marco Rubio on Monday, according to Axios. 

Barrot’s statement also came after reports in Arabic and Iranian media that Germany planned to activate snapback sanctions this week, which the German Foreign Ministry denied to Jewish Insider. A German official confirmed that his country shares France’s position.

Earlier this week, Tehran threatened a “proportionate and appropriate response” if the E3 snaps back sanctions, a move Iranian Foreign Ministry Spokesman Esmaeil Baqaei claimed “lacks any legal, political or moral justification.”

“European parties are constantly trying to use it as a tool in violation of their fundamental obligations,” he added.