WASHINGTON (Reuters) - The United States supports Europe’s move to initiate the dispute mechanism in Iran’s nuclear deal, the U.S. top envoy for Iran told Reuters on Tuesday, but would like to see Europeans join Washington in its efforts to diplomatically isolate Tehran.

FILE PHOTO: Brian Hook, U.S. Special Representative for Iran, attends a news conference in London, Britain June 28, 2019. REUTERS/Simon Dawson/File Photo

France, Britain and Germany formally triggered the dispute mechanism in Iran’s nuclear deal, the strongest step the Europeans have taken so far to enforce an agreement that requires Iran to curb its nuclear program.

U.S. President Donald Trump in 2018 abandoned the nuclear deal reached under predecessor Barack Obama, arguing it was too weak and that new sanctions would force Iran to accept more stringent terms. Iran says it will not negotiate with sanctions in place.

“We do support the Europeans initiating the dispute resolution mechanism. ... What the president has asked for is for them to leave the deal and join us in our diplomacy to get a new deal,” Brian Hook, U.S. special representative for Iran, said in an interview.

The three European nations said they still wanted the 2015 nuclear deal to succeed and were not joining a “maximum pressure” campaign by the United States.

UK Prime Minister Boris Johnson expressed willingness over a replacing it. “If we’re going to get rid of it, let’s replace it and let’s replace it with the Trump deal,” he said.

Hook said the United States was “very pleased” with Johnson agreeing with the U.S. assessment, adding that there wasn’t much left of the Iran nuclear deal.

Triggering the mechanism amounts to formally accusing Iran of violating the terms of the deal and could lead eventually to reimposing U.N. sanctions that were lifted under the pact.

After pulling out of the Iran deal, the United States snapped back sanctions on Iran and has gradually increased its “maximum pressure” campaign targeting the Islamic Republic’s revenues from oil, mining and other industries, and effectively scare off countries from doing business with Tehran.

Tensions boiled further after the United States this month killed Iran’s most powerful military commander in a drone strike after tit-for-tat exchanges between Washington and Tehran that began with the killing of an American contractor on a base in Iraq.

Trump has been calling on Europeans to do more against Iran, and the administration has been pressuring European capitals to ditch the deal. Hook on Tuesday repeated that call.

“We hope that the Europeans will continue to hold Iran accountable. We’d like them to join our diplomatic efforts, of diplomatic isolation and economic pressure which are the conditions to get to a new and better deal,” he said.