"Despite my strong inclination, I have not yet withdrawn the United States from the Iran nuclear deal", Trump said in a statement, saying the options were to fix "the deal's disastrous flaws or the United States will withdraw".
The top Iranian diplomat said the world has over the past centuries been characterized by a paradigm based on power and zero-sum games, "which has had no result for the people of the world but loss, violence, conflict, and killings".
"In absence of such an agreement [between the USA and European powers], the United States will not again waive sanctions in order to stay in the Iran nuclear deal".
French President Emmanuel Macron phoned Mr Trump on Thursday to call for "the strict application of the deal and the importance of all the signatories to respect it". "We believe that the JCPOA is an important outcome of multilateralism and a model of resolving global hot-spot issues through political and diplomatic means", Lu Kang said.
"If at any time I judge that such an agreement is not within reach, I will withdraw from the deal immediately", he added.
Iran has complained that USA sanctions not connected to nuclear activity have effectively cancelled out any financial benefits it expected from the 2015 deal.
President Trump is issuing a final waiver on Iran sanctions, the administration announced Friday.
If the president can get an agreement that "never expires", in place of the sunset clauses now in the JCPOA, then, "he would be open to remaining in such a modified deal", the official said.
On Thursday, the European Union and member states urged Trump not to withdraw form the agreement, with European Union foreign policy chief Federica Mogherini saying the deal is "working" and "making the world safer".
Instead of backing out of the nuclear deal, Trump has previously said he was giving lawmakers a chance to amend the Iran Nuclear Agreement Review Act, the 2015 bill that was passed as a way to impose a degree of congressional oversight over the agreement, it added.
Trump, who has sharply criticized the deal reached in Barack Obama's presidency, had chafed at having to once again waive sanctions on a country he sees as a threat in the Middle East.
The president wants Congress to modify a law that reviews US participation in the nuclear deal to include "trigger points" that, if violated, would lead to the United States reimposing its sanctions, the official said.
Additionally, the president is hoping that the Iran deal will require better United Nations inspections of Iran's nuclear sites and that Iran avoid a "breakout period" of being able to produce enough uranium for a nuclear bomb.
The other signatories to the deal - Britain, China, France, Germany and Russian Federation - and the European Union, which oversaw the talks, were watching carefully. The other parties to the agreement would have been unlikely to join the United States in reimposing sanctions.
The president is also directing more than a dozen new designations against Iranian entities, senior administration officials said.
Two EU diplomats said EU foreign ministers will discuss what to do now at their next regular meeting, scheduled for January 22 in Brussels.
Trump might not get much help on the deal from Congress either.
The pact is underpinned on the US side by a presidential waiver of nuclear-related sanctions on Iran's central bank.