Briitain, France, and Germany on Thursday warned Iran that further violations of the 2015 nuclear deal would force the European Union (EU) members to leave the agreement, BBC reported.
In their announcement, the trio said they would use a special dispute mechanism if Iran breaches the deal again.
Such a move could trigger the agreement's collapse and allow the United Nations to reinstate sanctions on Iran, BBC noted.
On Thursday, Iranian President Hassan Rouhani said he is willing to hold talks with the US - but only if the deal is implemented and Tehran is allowed to maintain its missile capabilities.
Also on Thursday, the UN's nuclear watchdog, the International Atomic Energy Agency (IAEA) reported that Iran had again breached the deal, by using advanced models of centrifuges to enrich uranium.
In August, IAEA found that Iran had increased its stock of enriched uranium and refined it to a higher purity than allowed.