The 2015 accord "is delivering on its goal which is guaranteeing that Iran doesn't develop nuclear weapons, the European Union is determined to preserve it", Mogherini said.
He further said to sign a presidential memorandum to begin reinstating United States nuclear sanctions on Iran.
On Tuesday, US President Donald Trump announced he was pulling out of a landmark deal curbing Iran's nuclear program and reintroducing sanctions on the Islamic republic and those who trade with it.
Officially known as the Joint Cooperation Plan of Action (JCPOA) and signed by the United States, Britain, France, Germany, and China in 2015 the deal allowed the United Nations' nuclear watchdog agency could regularly inspect Iran's nuclear program. "The U.S. decision makes no difference to the British assessments" as the country's national security depends on it.
Trump pulled out of the 2015 pact and promised to reinstate US sanctions because he does not believe that the agreement prevents Iran from getting atomic weapons. "We have already started constructive and mutually beneficial discussions on these issues, and the E3 is committed to continuing them", they said.
Soon after the United States announcement, Iran also ceased its business operations with the USA -based Boeing which was allowed to do business with Iran after the Iran Nuclear Deal was signed in 2015. Under US law, Trump must wait at least 180 days before imposing their most severe consequences, which includes targeting banks of countries that fail to appreciably cut their oil purchases from Iran.
Second, given the intense enmity between Israel and Iran, the Israeli government might well decide to preemptively attack Iran's nuclear facilities before Tehran reaches the breakout point. The United States has indicated it could make a dramatic switch of its current position from a hard-won support in the Obama administration to a negative one held by Israel but rejected by all other parties including Russian Federation.
"From this moment, the JCPOA is between Iran and five countries". Moscow, he said, could use its influence on Tehran to that end. "The Kremlin doesn't want a direct conflict between Iran and Israel, but if it were to happen, they have an interest in playing both sides", she said.