Britain, France and Germany have kickstarted a process that could lead to United Nations sanctions being reimposed on Iran and the collapse of the 2015 nuclear deal, after triggering the deal’s dispute resolution mechanism.

Officials described the move as one taken more in sorrow than anger and said it was in part prompted by fears Iran might be less than a year away from possessing the capacity to develop a nuclear bomb.

Concern was most acute that Iran will be learning about centrifuge enrichment in an irreversible way. “The concern is they are going to learn something that it is not possible for them to unlearn,” one senior official said.

The three nations said they rejected Tehran’s argument that Iran was justified in violating the deal because the United States broke the 2015 agreement by pulling out unilaterally in 2018.

“We have therefore been left with no choice, given Iran’s actions, but to register today our concerns that Iran is not meeting its commitments,” the countries said in a joint statement. They added the move did not mean the EU was joining the Trump administration’s campaign of maximum economic pressure on Iran.

The decision was taken in principle before Christmas by the three European powers, and not prompted by the recent Iranian attack on US bases in Iraq, or the Iranians’ accidental downing of the Ukrainian airliner.

The Iranian foreign ministry issued a relatively mild response saying: “If Europeans, instead of keeping to their commitments and making Iran benefit from the lifting of the sanctions, misuse the dispute resolution mechanism, they’ll need to be prepared for the consequences that they have been informed about earlier.”

The remarks seemed designed to be a warning that Europe should not go through the gears of the dispute mechanism quickly, something officials insist they will not do.

Germany’s foreign minister, Heiko Maas, said the three European countries “could no longer leave the growing Iranian violations of the nuclear agreement unanswered”.

“Our goal is clear: we want to preserve the accord and come to a diplomatic solution within the agreement,” he said. “We call on Iran to participate constructively in the negotiation process that is now beginning.”

Iran’s foreign ministry warned of a “serious and strong response”. Foreign ministry spokesman Abbas Mousavi added, however, that Iran was “fully ready to answer any good will and constructive effort” that preserves the deal.

Under the dispute resolution mechanism, countries have 30 days to resolve their problem, though that can be extended. If it cannot be solved, the matter could be brought before the UN security council and could then result in the snapback of sanctions that had been lifted under the deal.

Officials said the practical impact of reimposed sanctions would be low due to the swingeing nature of existing US sanctions. It would, however, represent a severe blow to the cause of multilateral nuclear non-proliferation.

A western diplomat said: “This allows us to buy time whilemaking clear to Iran that they cannot continue on this path of non-compliance with no consequences.”

Donald Trump has been pressing Europe to leave the nuclear deal ever since he unilaterally took the US out of deal in May 2018. In response, Iran has rolled back its commitments in stages to try and pressure the other countries involved to provide economic incentives to offset the American sanctions, but efforts from them so far have been insufficient.

The White House will be delighted that its sustained pressure has paid off. There is little expectation that Iran will respond to the EU’s move by reversing the steps it has already taken, especially on nuclear research and development.

In his strongest call yet from Europe for a new agreement to replace the 2015 deal, the British prime minister, Boris Johnson, said the way forward was to agree what he called a “Trump deal”.

“If we’re going to get rid of it, let’s replace it and let’s replace it with the Trump deal … President Trump is a great dealmaker, by his own account,” he said.

The UK’s foreign secretary, Dominic Raab, tried to finesse Johnson’s call by saying the existing deal was the best way to rein in Iran’s nuclear ambitions, but this did not preclude a search for a wider more ambitious deal covering Iran’s ballistic missiles and its regional behaviour. UK officials argue any such deal would require the US to suspend sanctions for negotiations to start, something Trump rejects.

Iran has taken its five successive steps away from the deal because it says the EU has not fulfilled its commitment to boost trade. The US has imposed extra-territorial sanctions making it nearly impossible for European firms to trade with Iran and not risk swingeing US fines. A mechanism designed to circumvent the sanctions set up by the EU has so far failed to facilitate a single transaction between European firms and Iran.

European diplomats stressed the move was not being taken to reimpose sanctions, but to try to find some way to press Iran to come back into compliance with the deal. Josep Borrell, the EU’s foreign affairs high representative, even went so far as to say that preserving the nuclear deal “is more important than ever”.

Iran says it no longer feels bound to comply with aspects of the deal except allowing UN inspectors into its sites.

The EU, following long talks with Russia and China about its plan, said it was hopeful that Tehran would not react by banning the UN inspectors.

European diplomats remain sceptical that Trump’s policy of maximum economic pressure will persuade Iran to renegotiate the deal, and fear it will instead strengthen the position of hardliners in Tehran. The street protests in Tehran have not changed that EU judgment.