The ambassadors of the three nations to the U.N. met on Tuesday to discuss the matter. U.S. Secretary of State Marco Rubio also discussed Iran’s nuclear program in a phone call the day before, according to U.S. officials.

“Without a firm, tangible and verifiable commitment from Iran, we will do so by the end of August at the latest,” French foreign minister Jean-Noël Barrot said, adding that the nations are “justified” in doing so.

The European nations are hoping this pressure will convince the Iranian regime to restore its cooperation with the International Atomic Energy Agency. The Islamic Republic implemented a law in July suspending cooperation with the agency and expelled its members.