Mike Pompeo has set the US on a collision course with most of its UN partners in an attempt to extend the isolation of Iran.

Instead it was the US which appeared beleaguered, with Pompeo clashing bitterly with European allies, emphasising a deepening Transatlantic rift.

The US secretary of state went to the UN on Thursday to set in motion the diplomatic gambit, claiming the US is still a participant in the 2015 nuclear deal with Iran – from which Donald Trump explicitly withdrew two years ago – and therefore retains the right under the rules of the deal to trigger a “snapback” or resumption of full UN sanctions.

Very few other UN member states think the US has the authority to do this. Even before he made a scheduled announcement at the UN headquarters in New York, the UK, France and Germany, issued a statement saying the the US was not a participant and they would not support it.

In response, Pompeo denounced the Europeans as having chose to “side with the Ayatollahs”

“Their actions endanger the people of Iraq of Yemen, Lebanon, Syria, and indeed their own citizens as well,” he told reporters. “America won’t join in this failure of leadership. America will not appease. America will lead.”

The extent of US isolation was illustrated by a related vote in the security council last week, in which it received support from the Dominican Republic alone, despite an intense and targeted lobbying campaign.

Pompeo met the UN secretary general, António Guterres, and the current chair of the UN security council, the Indonesian permanent representative, Dian Triansyah Djani, in New York on Thursday, to deliver formal notice that the US considers Iran to be in non-compliance with the 2015 nuclear deal, known as the Joint Comprehensive Plan of Action (JCPOA).

The snapback mechanism was written into the JCPOA to give the parties to the deal confidence that any one of them could reimpose sanctions if Iran violated the agreement. It was not intended for a state that had left the agreement to exploit it. The US is claiming still to be a JCPOA participant through a legal technicality, based largely on the fact that it is named as a participant in a UN resolution endorsing the JCPOA. But that stance was quickly rejected by European governments.

“France, Germany and the United Kingdom (“the E3”) note that the US ceased to be a participant to the JCPoA following their withdrawal from the deal on May 8, 2018,” a joint letter from the three governments said. “We cannot therefore support this action which is incompatible with our current efforts to support the JCPOA.”

After a notice of non-compliance has been served, there is a 30-day window after which, in the absence of a security council resolution to the contrary, all UN sanctions in place under the 2015 deal will snap back into place.

It is likely Pompeo has timed his visit to the UN so that the month-long grace period will end in time for Donald Trump’s speech to the UN general assembly summit in the last week of September, allowing the president to declare that UN sanctions have been restored.

It is likely most other member states, including the majority of US allies, will disagree on the grounds that the US has no right to use the mechanism. The US is seeking to rally support and to put particular pressure on the UK, which has thus far stuck with European powers on the issue.

Richard Gowan, the UN director at the International Crisis Group, said that US leaks earlier in the year, revealing that it had threatened the UK and other European countries with sanctions if they did not take action against Iran, had backfired.

“That was an exceedingly stupid move because, especially in London, ministers were deeply offended that the US was treating them in this way, and actually that was probably the first moment that the Johnson administration in London started to stiffen its spine, and wonder whether it really wanted to end up supporting the US in this process,” Gowan said.

The outcome is expected to be messy, with conflicting versions of reality, and no clear adjudicator. The matter could be referred to the international court of justice in The Hague, but a ruling could take a year.

Ellie Geranmayeh, a senior policy fellow at the European Council on Foreign Relations said: “Other nations appear poised to treat it like a tirade from a rampaging toddler and hope that the US swiftly grows out of its maximum pressure phase.”

Wendy Sherman, a former state department official who was lead US negotiator on the JCPOA, said: “This is really a process that will just be mucked around in the procedural political process of the United Nations, and at the end of the day, we’ll go out with a whimper, not with a bang.”

Confusion may suit the Trump administration, which would be seen domestically as tough on Iran and the UN. It will also make banks and companies more skittish about financing Iranian purchases of even humanitarian goods on the global market, increasing pressure on Tehran.

Most observers believe Trump and Pompeo’s ultimate aim is to provoke Iran into retaliatory action, formal withdrawal from the JCPOA and expulsion of nuclear inspectors, for example, which will make it impossible to salvage the 2015 agreement even if Joe Biden wins the presidency in November.