Ammon News - The foreign ministers of France, Germany, the U.K. and the EU foreign policy chief told Secretary of State Marco Rubio they will trigger the "snapback" sanctions mechanism against Iran on Thursday, three sources with direct knowledge told Axios.

The "snapback" mechanism automatically reimposes all UN Security Council sanctions that were lifted under the 2015 Iran nuclear deal.

The move is expected to increase the economic pressure on Iran and likely lead to an Iranian retaliation.

Iranian officials have threatened in the past that triggering the "snapback" mechanism would lead itr to withdraw from the nuclear non-proliferation treaty (NPT).

The State Department declined to comment on the matter.

France, Germany and the U.K. gave Iran until the end of August to take steps regarding their nuclear program to avoid from the triggering of the UN sanctions.

The European powers wanted Iran to resume negotiations with the U.S. over a nuclear deal, allow full access to UN inspectors and give access to its 60% highly enriched uranium stockpile.

A source with knowledge of the Geneva meeting said the Iranians "haven't put tangible detailed deliverables on the table", closed the door on the possibility of extending the deadline for the "snapback" and paving the way for reimposing the sanctions.

"The E3 leaders think that Iran has been for years in clear violation of its obligations under the 2015 nuclear deal, with no concrete steps taken to remedy that situation," a European diplomat said explaining to decision to trigger the "snapback".

Iran's deputy foreign minister Kazem Gharibabadi told Iranian state television that if the Europeans trigger the "Snapback" Iran will retaliate, including suspension of cooperation with the IAEA.

The process of activating "snapback" takes 30 days, and the Europeans want to conclude the process before Russia assumes the UN Security Council presidency in October.

"Triggering the snapback process would not mean the end of diplomacy. The E3 remain open to engaging with Iran in the weeks until the UN sanctions will come into effect", a European diplomat said.