The European Union vowed on Monday to defend a 2015 nuclear deal between Iran and world powers and urged US lawmakers not to reimpose sanctions after President Donald Trump chose not to certify Tehran's compliance with the accord.
Germany and France led a chorus of warnings to the United States, normally the EU's closest foreign policy ally, that any weakening of the agreement to prevent Iran obtaining nuclear weapons could have serious consequences for peace.
"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 at a meeting with his EU counterparts.
EU foreign policy chief Federica Mogherini, who chaired the final phase of the 2015 negotiations, held closed-door talks on how the 28-nation bloc should proceed and ministers were also set to discuss how to tackle Iran's ballistic missile programme.
Mogherini has insisted the nuclear deal is working, while the International Atomic Energy Agency (IAEA) says Iran is complying. Trump has dubbed it "the worst deal ever negotiated".
"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."