Britain, France and Germany said on Thursday they would retain ballistic missile and nuclear proliferation-related sanctions on Iran that were set to expire in October under the 2015 Iran nuclear deal, a step that could provoke Iranian retaliation.

Reuters first reported in June that European diplomats had told Iran they planned to keep the measures.

“In direct response to Iran’s consistent and severe non-compliance with its JCPoA commitments since 2019, the governments of France, Germany, and the United Kingdom intend to maintain nuclear proliferation-related measures on Iran, as well as arms and missile embargoes, after Joint Comprehensive Plan of Action (JCPoA) Transition Day on 18 October 2023,” a spokesperson for the three countries, known as the E3, said in a statement.

European sources had cited three reasons for keeping the sanctions: Russia’s use of Iranian drones against Ukraine; the possibility Iran might transfer ballistic missiles to Russia; and depriving Iran of the nuclear deal’s benefits given Tehran has violated the accord, albeit only after the United States did so first.

Iran rejected the decision as “illegal and provocative”.

“Undoubtedly, Iran will respond appropriately to this .... action which clearly violates the obligations of the EU, France, Germany and Britain under the JCPOA and the Resolution 2231,” Iran’s foreign ministry said in a statement, referring to a UN resolution that endorsed the 2015 nuclear pact.

The deal’s coordinator, EU foreign policy chief Josep Borrell said he had received a letter from the E3 informing him of their decision and transferred it to Iran, China and Russia, the other participants to the deal.

“As Coordinator, I will consult with all JCPoA participants on the way ahead,” he said.

Keeping the sanctions would reflect Western efforts to prevent Iran from developing nuclear weapons and the means to deliver them despite the collapse of the 2015 deal, which then-US President Donald Trump abandoned in 2018.

The JCPoA agreed with Iran in 2015 envisaged a “Transition Day” eight years later, when remaining ballistic missile and nuclear-related sanctions on Iran would be lifted.

But Britain, France and Germany will now transfer UN sanctions on Iran that are due to be lifted next month into domestic law, while Britain and the EU will retain existing sanctions, Britain’s Foreign office said in a statement.

The crux of the JCPoA pact, which Iran made with Britain, China, France, Germany, Russia and the US, limited Tehran’s nuclear program making it harder for it to get fissile material for a bomb in return for relief from economic sanctions.

As a result of Trump’s withdrawal from the deal and US President Joe Biden’s failure to revive it, Iran could make the fissile material for one bomb in 12 days or so, according to US estimates, down from a year when the accord was in force.

“Our commitment to finding a diplomatic solution remains. This decision does not amount to imposing additional sanctions nor to triggering the snapback mechanism. We stand ready to reverse our decision, should Iran fully implement its JCPoA commitments,” the E3 said, referring to a mechanism that would immediately restore all UN sanctions against Iran.