British Prime Minister Theresa May, German Chancellor Angela Merkel and French President Emmanuel Macron | Ludovic Marin/AFP via Getty Images Macron, Merkel, May express ‘regret’ at Trump’s Iran move European powers pledge their continued support for the Iran nuclear deal.

The leaders of France, Germany and the U.K. expressed "regret and concern" over Donald Trump's decision to reimpose U.S. nuclear sanctions on Iran Tuesday.

Emmanuel Macron, Angela Merkel and Theresa May spoke by phone to discuss Trump's decision, a Downing Street spokesperson said, "and agreed their continuing commitment" to the pact.

In a joint statement, the three European leaders said, "Together, we emphasise our continuing commitment to the JCPoA [Joint Comprehensive Plan of Action]. This agreement remains important for our shared security.

"We urge all sides to remain committed to its full implementation and to act in a spirit of responsibility."

They said the "world is a safer place as a result" of the deal.

"We urge the U.S. to ensure that the structures of the JCPoA can remain intact, and to avoid taking action which obstructs its full implementation by all other parties to the deal."

They also urged "Iran to show restraint in response to the decision by the U.S."

The EU's foreign policy chief, Federica Mogherini, said "the European Union will remain committed to the continued full and effective implementation of the nuclear deal."

Giving a televised statement from Rome, she said "the nuclear deal with Iran is crucial for the security of the region, of Europe, and of the entire world.

"The nuclear deal with Iran is the culmination of 12 years of diplomacy. It belongs to the entire international community. It has been working and it is delivering on its goal, which is guaranteeing that Iran doesn’t develop nuclear weapons. The European Union is determined to preserve it."

Earlier, Trump said: "I am announcing today that the United States will withdraw from the Iran nuclear deal. We will be instituting the highest level of economic sanction."

Trump did not offer details about the reimposition of sanctions, whose structure is complex. But in a conference call with reporters shortly after the president spoke, his national security adviser, John Bolton, himself a fierce critic of Iran, suggested that the president is taking a maximalist path: "The decision that the president signed today puts sanctions back in place immediately ... We're out of the deal."