VIENNA, Austria: France, the United Kingdom, and Germany have warned that they may trigger the "snapback mechanism," which would automatically restore all United Nations sanctions on Iran.

The three countries, known as the E3, argue that Iran has deliberately moved away from the commitments it made under the 2015 nuclear agreement. That deal had lifted sanctions in exchange for strict limits on Iran's nuclear program.

The sanctions that could return are tough. They include bans on selling conventional weapons to Iran, restrictions on developing ballistic missiles, freezing assets, travel bans for key officials, and a ban on producing nuclear-related technology.

In July, the E3 offered Iran a chance to delay the snapback, but only if Tehran agreed to three conditions: restarting talks with the United States about its nuclear program, giving U.N. inspectors full access to its nuclear sites, and explaining the more than 400 kilograms of highly enriched uranium it has produced. Iran refused. Today, it is enriching uranium at levels very close to what is needed to make a nuclear weapon.

Earlier this year, the U.S. and Iran tried to reach a new nuclear deal. But the talks collapsed after Israel launched a 12-day bombardment of Iran's nuclear and military facilities, followed by U.S. strikes on June 22.

Under the 2015 deal, known as the Joint Comprehensive Plan of Action (JCPOA), Iran agreed to enrich uranium only up to 3.67 percent, enough for civilian power, not weapons. In return, global sanctions were lifted, and the International Atomic Energy Agency (IAEA) was tasked with monitoring Iran's compliance.

The snapback process works like this: if any country in the deal reports Iran's failure to meet its commitments, the U.N. Security Council has 30 days to adopt a resolution continuing sanctions relief. However, the U.S., Britain, or France could easily veto such a resolution. If that happens, all pre-2015 sanctions automatically return, with no further vote required.

Timing matters. The snapback power expires on October 18. After that, any new sanctions would need approval from the Security Council, and Russia and China could veto them. For this reason, European nations want to trigger snapback in September, when South Korea holds the rotating presidency of the Council, before Russia takes over in October.

The IAEA has raised serious concerns. In May, it reported that Iran had stockpiled more than 9,200 kilograms of enriched uranium, far above the 300-kilogram limit in the JCPOA. Of this, over 400 kilograms were enriched to 60 percent purity. If taken to 90 percent, that amount could make about nine nuclear weapons, though additional technology would still be required.

Iran, however, insists its nuclear program is peaceful. It argues that since the U.S. abandoned the deal in 2018, it is no longer bound by its limits. It also claims that the E3 has no legal right to bring back sanctions. Tehran has even threatened to leave the Nuclear Non-Proliferation Treaty if snapback is used.

Some analysts believe there is still a narrow chance for diplomacy. If Iran and the West find common ground during the 30-day snapback window, they could delay the expiration date and keep talks alive. But without a new agreement, experts warn the crisis will return again and again.