PARIS/BRUSSELS — France, Britain and Germany have sent an official diplomatic warning to Iran about the serious consequences Tehran faces if it scales back its compliance with the 2015 nuclear deal, two European diplomats said on Monday.

Three diplomats said the European signatories to the deal lodged the diplomatic demarche, the term for a formal note, on June 22, with two saying the communication aimed to warn Iran specifically against scaling back its commitments to the accord.

It was not immediately clear what consequences Iran might face for non-compliance.

Iran has said it will not give the European powers more time beyond July 8 to save the nuclear deal. It has said it is ready to go through with a threat to enrich uranium to a higher level if Europe cannot shield Tehran from US sanctions.

The move by the Europeans highlights the growing frustration they have with Iran, which has put the onus on them to do more to shield Tehran from the crippling impact of sanctions.

"They have made the strategic choice to blame the Europeans for everything," said one diplomat. "The more the Iranians do things that potentially violate the accord, the less inclined we are to make efforts to help them. It's a vicious circle."

It was unclear whether Iran had responded to the European demarche, although Deputy Foreign Minister Abbas Araqchi was quoted by state TV on June 23 as saying it would not back down on its decision to scale back commitments.

The three European powers, along with Russia and China, have been trying to salvage the nuclear agreement since the United States pulled out of it in May 2018 and reimposed sanctions that have hit the Iranian economy hard.

Among the steps Europe has taken is the creation of a limited trade mechanism intended to make it possible for countries to go on trading with Iran outside the scope of the US sanctions. But the mechanism is not yet operational.

Iranian officials were not immediately available for comment. — Reuters