"The response from Iran, and in fact from the international community to the US move would be very unpleasant for Americans," he added.
The 2015 Joint Comprehensive Plan of Action, the official name for the Iran nuclear deal, saw economic sanctions lifted on Iran in return for strict limits on its nuclear programme.
The Iran nuclear deal was signed by former US President Barack Obama, but Trump has consistently called it “a very bad deal.”
Trump has set a deadline of May 12 to ‘fix the terrible flaws’ or he will refuse to extend sanctions relief on Iran. The US remains in the deal by periodically waiving nuclear sanctions against Iran.
Trump is concerned by Iran’s ballistic missile programme and by how fast they could add a nuclear capability at the end of the deal and the country’s stance in the Middle East, notably Tehran’s role in backing Syria’s government in the civil war and fighting a proxy war against Saudi Arabia in Yemen.
A leaked report in January claims that Iran has fired at least 23 ballistic missiles since signing the 2015 nuclear deal.
The Iran nuclear deal was signed by six of the world major powers - Britain, the US, Russia, France, China, and Germany - plus the European Union.
When Trump waived sanctions against Iran in January he warned European allies that it will be the last time unless they agree to make radical changes.
He said: “This is the last chance.
“I hereby call on key European countries to join with the United States in fixing significant flaws in the deal, countering Iranian aggression, and supporting the Iranian people.
“If other nations fail to act during this time, I will terminate our deal with Iran.”
Britain, France, and Germany have been engaged in “intensive talks” with Washington to maintain support for the Iran nuclear deal beyond the May 12 deadline, but nothing has yet to be agreed.
US Senator Bob Corker, chairman of the Senate Foreign Relations Committee, said last month that he believes Trump will pull out of the Iran nuclear deal.
He said: “Right now it doesn't feel like it's going to be extended.
“I think the president likely will move away from it unless our European counterparts really come together on a framework.”