Salehi made the comments after a meeting with members of the Iranian Parliament's Committee on National Security and Foreign Policy held on Tuesday to discuss the AEOI's capabilities in dealing with US President Donald Trump's move to pull Washington out of the nuclear agreement, officially known as the Joint Comprehensive Plan of Action (JCPOA).
"If the Europeans do not give assurances, we are ready to return to much more advanced conditions than before the [signing of the] JCPOA," Iran's nuclear chief said.
He confirmed Iran's true and real preparedness to return to conditions it had before signing the nuclear accord but expressed hope that the country would see no such necessity, Presstv Reported.
The US president announced on May 8 that Washington was walking away from the JCPOA, which was reached between Iran and the five permanent members of the UN Security Council -- the US, Britain, France, Russia and China -- plus Germany.
Trump also said he would reinstate US nuclear sanctions on Iran and impose "the highest level" of economic bans on the Islamic Republic.
Iran has said it would remain in the JCPOA for now, pending negotiations with the other signatories in the coming weeks before making a final decision on its future role in the agreement. Tehran wants the Europeans to give it clear-cut guarantees about fulfilling their obligations if it remains in the accord.
Iranian President Hassan Rouhani said on Tuesday that all countries, particularly member states of the European Union, must stand up to the United States' "illegal and illogical" move to withdraw from the key nuclear agreement.
"Iran can stay in the JCPOA only if it fully benefits from it," Rouhani said.
In an effort to try and rescue the nuclear deal, Iranian Foreign Minister Mohammad Javad Zarif launched a diplomatic tour early on Sunday which took him to Brussels following visits to Beijing and Moscow. He began the visit on President Rouhani's order to sound out Europe and other parties to the JCPOA about the possibility of keeping the deal in place.
Zarif on Tuesday met EU foreign policy chief Federica Mogherini ahead of evening talks with his counterparts from Britain, France and Germany. The three European signatories to the JCPOA have expressed their determination to preserve the landmark Iran nuclear deal.