Iran's Foreign Minister Javad Zarif sought further talks after failing to win any concrete assurance to help tackle the USA threat of economic sanctions over its nuclear program.
"We will look at potential options for supporting continued sanctions relief for Iran to ensure we meet our commitments under the deal, as well as calling on Iran to continue to abide by the restrictions the deal places upon their nuclear program", he said.
According to him, Araghchi told the commission that if Iran does not receive such guarantees from European leaders it would have to "take the necessary decisions".
So far, China, France, Russia, Britain, the European Union and Iran remain in the accord, which placed controls on Iran's nuclear program and led to a relaxation of USA economic sanctions against Iran and companies doing business there.
The top Iranian diplomat made the comments at a meeting on Monday with his Russian counterpart, Sergei Lavrov, in Moscow, the second destination on his diplomatic tour aimed at saving the nuclear deal, officially called the Joint Comprehensive Plan of Action (JCPOA). He will also have similar discussions with France, Germany and Britain on Tuesday.
National security adviser John Bolton said Sunday he believes European nations will ultimately join the USA and leave the Iran nuclear agreement.
Iran's foreign minister says talks with the EU's foreign policy chief in Brussels were "constructive".
China has maintained investment and trade relations with Iran, even under the economic sanctions from Western nations before the nuclear deal.
"Our trade with New Zealand is the importing dairy products from NZ, if they want to impose sanctions then they must ban the companies from exporting the commodities to Iran".
But the reach of the U.S. financial system, the dominance of the USA dollar, Trump's efforts to weaken the WTO and the presence of European companies' operations in the United States all weaken any potential EU measures.
The EU insists the deal is working, pointing to repeated United Nations inspections verifying the Islamic republic's compliance with its side of the bargain, and Mogherini's spokeswoman Maja Kocijancic told AFP ahead Zarif's arrival that "we must do our utmost to preserve it".
They could consider retaliatory sanctions using the EU's so-called blocking statute that bans any European Union company from complying with USA sanctions and does not recognise any court rulings that enforce American penalties.
The White House also has bluntly warned Iran of unspecified consequences should it resume nuclear activities prohibited under the agreement.
Tehran has expressed its opposition to Trump's move.
"The Europeans, after the withdrawal of the United States from the deal, have found themselves forced to save the Joint Cooperative Plan of Action themselves", he added.