"Our governments remain committed to ensuring the agreement is upheld, and will work with all the remaining parties to the deal to ensure this remains the case including through ensuring the continuing economic benefits to the Iranian people that are linked to the agreement," said a joint statement.

The statement from British Prime Minister Theresa May, German Chancellor Angela Merkel and French President Emmanuel Macron suggests a transatlantic clash is looming over Trump's decision amid warnings for European firms working in Iran that they could be subject to sanctions.

"We urge the US to ensure that the structures of the JCPoA (Iran deal) can remain intact, and to avoid taking action which obstructs its full implementation by all other parties to the deal," the joint statement said.

It added that Trump's decision had been noted with "regret and concern" and it urged Iran to continue complying with its obligations.

"We encourage Iran to show restraint in response to the decision by the US; Iran must continue to meet its own obligations under the deal," it added.