The European Union's foreign policy chief says the EU is reluctant to change the landmark nuclear agreement with Iran even as U.S. President Donald Trump threatens to walk away from the pact.

Federica Mogherini said Monday after chairing talks among the foreign ministers of EU countries that Europeans "attach strategic importance to the full implementation of the agreement by all parties."

Mogherini said: "It is for us a matter of security, for Europe and for the rest of the world."

The EU's representative for foreign affairs and security policy says the pact, "if disrupted, would create an additional security threat and concern in the region."

Mogherini says the EU hopes to dissuade Iran from developing missiles or undermining regional security, but that work must happen "outside the scope of the nuclear agreement."