'Total termination' of Iran nuclear deal possible: Trump

US President Donald Trump said Monday that a "total termination" of the Iran nuclear deal remains possible, after refusing to certify the 2015 accord and leaving its fate to Congress.

Speaking to reporters ahead of a cabinet meeting, he said: "I feel strongly about what I did I'm tired of being taken advantage of.

"It might be total termination, that's a real possibility, some would say that's a greater possibility."

His comments came as the EU announced it was sending its chief diplomat to Washington next month to fight to save an accord that saw Tehran dramatically scale back its nuclear ambitions in return for an end to punishing sanctions.

Trump alarmed allies across the Atlantic with a belligerent speech on Friday in which he stopped short of pulling out of the agreement but warned he could do so at any time, restating his belief the deal was letting Iran off the hook.

'Non-proliferation is a major element of world security and rupturing that would be extremely damaging'

- French Foreign Minister Jean-Yves Le Drian

EU ministers have warned that ditching the deal when Iran has repeatedly been certified as keeping up its end of the bargain would send a signal to North Korea that negotiating with the international community is a waste of time.

After a meeting in Luxembourg, EU ministers said a failure to uphold the international agreement could have serious consequences for regional peace, and also undermine efforts to check North Korea's nuclear ambitions.

"As Europeans together, we are very worried that the decision of the US president could lead us back into military confrontation with Iran," German Foreign Minister Sigmar Gabriel told reporters.

After a closed-door meeting chaired by EU foreign policy chief Federica Mogherini on Iran, the ministers issued a joint statement saying the 2015 deal was key to preventing the global spread of nuclear weapons.

"The EU is committed to the continued full and effective implementation of all parts of the JCPOA," it said, referring to the Joint Comprehensive Plan of Action, the formal name of the accord with Iran agreed in July 2015 in Vienna.

"Non-proliferation is a major element of world security and rupturing that would be extremely damaging," French Foreign Minister Jean-Yves Le Drian told reporters. "We hope that Congress does not put this accord in jeopardy."

Mogherini said she would travel to Washington early next month to try to muster support for the accord.

Britain and France are firmly committed to the nuclear deal and will work to ensure it is enforced, British Prime Minister Theresa May's office said on Monday after she spoke to French President Macron.

May and Macron said that France and Britain would work together to "push back on Iran's destabilising activity in the region," May's office said in a statement after the phone call. 

There is broad support among US lawmakers for fresh pressure on Iran over its continued missile development and subversive activities in the region - factors that Trump says violate the "spirit" of the agreement

Tehran has warned such action would mean Washington had broken its end of the bargain, and thus likely signal the end of their own compliance.