President Donald Trump signed an executive order on Monday restricting purchases of dollar banknotes by Iran, preventing the government from trading gold and other precious metals and blocking the nation from selling or acquiring various industrial metals. Further sanctions on Iran's lucrative oil industry and energy sector are due to follow in November.
US National Security Adviser John Bolton said Iran "could take up the president's offer to negotiate with them, to give up their ballistic missile and nuclear weapons programmes fully and really verifiably - not under the onerous terms of the Iran nuclear deal, which really are not satisfactory".
The EU wants to preserve the economic relation reestablish between both partners within the framework of the Joint Comprehensive Plan of Action (JCPOA), also known as the Iran nuclear deal, to try to save the agreement.
The two other signatories to the 2015 pact - Russian Federation and China - also continue to support it.
"Since the deal was reached, Iran's aggression has only increased", Trump said.
Iran's rial currency has lost half its value since April under the threat of revived USA sanctions. He dismissed a U.S. call for talks, saying "we are always in favour of diplomacy and talks..."
"Consistent with President Trump's decision, the administration will be reimposing specified sanctions after August 6, the final day of the 90-day wind-down period", the White House said. "If the USA government is willing, let's start right now".
20 killed in World War II plane crash in Switzerland
The crash happened hours after a family of four were killed when their small plane went down further west in the Swiss Alps. The area around the crash site, which is popular with hikers and skiers and includes a glacier, was closed to the public.
The United States continues to stand with the long-suffering Iranian people, who are the rightful heirs to Iran's rich heritage and the real victims of the regime's policies, indicated the statement.
Other countries have also asked European Union officials for details on the blocking regulations, as they explore ways to bypass sanctions.
"If you stab someone with a knife and then you say you want talks, then the first thing you have to do is remove the knife", Rouhani said in a speech broadcast live on state television. "But talks need honesty", Rouhani said.
Foreign Office minister Alistair Burt has moved to reassure businesses they will not face legal action in connection with deals with Iranian firms.
He said Washington was becoming isolated internationally and would come to regret imposing sanctions against the views of its allies and other world powers.
Many large European firms are leaving Iran for fear of United States penalties, and Mr Trump warned of "severe consequences" against firms and individuals that continued to do business with Iran.
British Minister of State for the Middle East Alistair Burt said Europe can protect its companies from new USA sanctions which were reinstated on Tuesday, as the European Union activated a blocking statute to insulate firms against any fallout.