The decision to stay in the deal, at least for now, comes as its critics and proponents argue over whether recent antigovernment protests in Iran show that the worldwide accord has helped, or hurt, the Islamic Republic's authoritarian clerical leadership.
Zarif tweeted that the Brussels meeting had shown a "strong consensus" that Iran was complying with the pact, had the right to enjoy its economic benefits and "any move that undermines (it) is unacceptable".
People rally in support of Iranian anti-government protests in Los Angeles on Saturday.
American partners in the deal including Russia, China, Germany, France, the United Kingdom and the European Union breathed a collective sigh of relief that the USA did not withdraw.
The meeting comes amid continued uncertainty on the Trump's administration's plans regarding the global agreement.
Javadanfan said that even if the U.S. imposes sanctions, "it's not at all certain that Iran will re-start its nuclear enrichment program because they won't want to lose European trading partners".
"We do not hide other disagreements, which exist. both in the ballistic field and over Iran's actions in the whole region", Le Drian said.
But the European envoys also questioned Iran's foreign minister, Mohammed Javad Zarif, over disputes such as the country's missile program and its role in Syria's war as a key ally of President Bashar Assad.
Iran has insisted its nuclear program was exclusively peaceful in nature.
US President Donald Trump wants to amend the deal or withdraw from it. Absent a violation, there is no reason to scrap an agreement that prevents Iran from developing a nuclear weapon. Some argue the European Union proponents of the agreement are hypocritically undermining their own defense of the Tehran government when they defend the nuclear deal but criticize the regime for the "unacceptable loss of human life" and denial of "fundamental rights".
United States officials said the measures would target Iranian businesses and arms dealing middlemen. Mr Straw detected a "pretty high degree of questioning about where Iran goes", he told the Guardian newspaper.
"President Trump claimed that "Bob Corker gave us the Iran deal" compromise", said one veteran foreign policy adviser involved in the discussions.
"The deal is working, it is delivering on its main goal which means keeping the Iranian nuclear programme in check and under close surveillance", Mrs Mogherini said.
Officials in the Trump administration have suggested that Trump plans to extend the waivers that lifted sanctions on Iran, but could seek new measures over issues such as human rights issues and missile programs.