Federica Mogherini said that the nuclear deal didn't require additional work or any amendments.
Iranian Foreign Minister Mohammad Javad Zarif, who is on a three-stop tour for exchanging views with the other signatory states of the JCPOA than US after the unilateral withdrawal of US President Trump from the agreement, commented on his first two stops on his Twitter page.
The top official has reemphasized the country's position on the Joint Comprehensive Plan of Action, commonly to as the Iran nuclear deal: in particular, that country plans to receive the economic benefits from the agreement, which were initially stipulated in it.
But we also remain concerned how President Trump's scrubbing of the Iran deal will impact future diplomatic negotiations with Kim Jong Un. "I believe it's a good start", he added.
When pressed by CNN on whether the administration would sanction European firms that continue to do business with Iran, Bolton said, "I think the Europeans will see that it's in their interest ultimately to come along with us".
Trump's withdrawal from the deal has imperiled not only the accord, but the threat of sanctions could trickle down to European companies doing business with Iran. Then he left Moscow for Brussels where he is slated to meet with the foreign ministers of UK, Germany, and France as well as the EU High Representative Mogherini.
Perry Cammack, of the Carnegie Middle East foundation, said "The primary target of U.S. secondary sanctions is not Iran itself but foreign financial institutions that trade with it".
Washington's decision to go against its European allies' advice and abandon the deal has pushed them closer to Beijing and Moscow as diplomats scramble to keep the pact alive.
Mogherini acknowledged the enormous challenge of finding a way around USA sanctions punishing businesses trading with Iran, which apply all around the world.
It comes after Iranian President Hassan Rohani confirmed Tehran would remain in the nuclear accord provided that the nation's interests were protected.
White House National Security adviser John Bolton on Sunday said U.S. sanctions on European companies that do business with Iran were "possible, but Secretary of State Mike Pompeo said he remained hopeful Washington and its allies could strike a new nuclear deal with Tehran". In a separate interview on CNN's "State of the Union, " he said Iran's economic condition is "really quite shaky, " so the impact of sanctions "could be dramatic".
Trump's decision to reimpose Iran-related sanctions would act as an "electrified rail" to those wanting to do business with the country, his British counterpart Boris Johnson added.
After long negotiations, Iran agreed in July 2015 to freeze its nuclear program in return for the repeal of punishing global sanctions.
In a pre-emptive strike on Tuesday, the U.S. treasury imposed new sanctions on the governor of the Iranian central bank, Valiollah Seif, and the Iraq-based Al-Bilad Islamic Bank - in both cases for allegedly moving millions of dollars to Hezbollah on behalf of Iran's Revolutionary Guards.
The EU's energy commissioner is also traveling this week to Iran to discuss strengthening European energy support to Iran.
They include retaliatory sanctions, allowing the European Investment Bank to invest directly in Iran and coordinating euro-denominated credit lines from European governments.
German exports to Iran totalled almost €3bn (£2.6bn) in 2017, while French exports soared from €562m in 2015 to €1.5bn in 2017.