European powers have urged the U.S. not to abandon the 2015 agreement with Iran that limits its nuclear programme, saying it is making the world safer.
Trump made the threat Friday as he extended waivers of key economic sanctions on Iran, keeping the accord alive at least for now. In October, in a measure required every 90 days under US law, Trump declined to certify that the agreement was in USA national security interests.
"One of the things that should be noted, and it's often overlooked, is that the sanctions that were imposed on Iran's ballistic missile programs are still in place", he says.
"While Britain may move to support the USA on this, Germany and France are likely to be strongly opposed", he said.
"Despite my strong inclination, I have not yet withdrawn the United States from the Iran nuclear deal", Trump said in a statement, warning that the options were to fix "the deal's disastrous flaws, or the United States will withdraw". "This is a last chance".
Germany, France, Britain and the European Union are "fully aware that Iran's continued compliance [is] conditioned on full compliance by the US", Iranian Foreign Minister Mohammad Javad Zarif warned on Twitter following talks in Brussels with his German, French and British counterparts, as well as European Union foreign policy chief Federica Mogherini.
In a tweet following Trump's harsh stance, Iranian Foreign Minister Mohammad Javad Zarif said Friday that it was a "desperate attempt" to undermine an accord which Iran insisted was "not renegotiable". He added that the European parties are "fully aware that Iran's continued compliance (is) conditioned on full compliance by the U.S.".
Trump said he wants Congress to fix "the deal's many flaws" such as existing sunset provisions.
"His (Trump's) cabinet does not want him to cancel the nuclear deal because it could open up the region to nuclear proliferation", Darrell West, a senior fellow at the Washington-based think tank Brookings Institute, told Xinhua. All of the other participants in the deal - including US allies in Europe - have said Iran is honoring the agreement.
Trump laid out conditions to keep Washington in the deal.
Trump and his top advisers have been negotiating with USA lawmakers on Capitol Hill to try to change sanctions legislation so that Trump does not face a deadline on whether to recertify Iranian compliance with the nuclear deal every 90 days. "We should be doing everything humanly possible to support, to encourage those protests, to tell the Iranian people, we stand with you". The next deadline for extending nuclear sanctions relief will come in mid-May.
Mr Trump maintains that Iran is not complying with the spirit of the deal, despite his own advisors previously admitting there had been no technical violations. The president came close to making such a promise in a tweet on New Year's Day that began with "Iran is failing at every level despite the awful deal made with them by the Obama Administration" and ended with the exclamation "TIME FOR CHANGE!"
"The decision had been expected since earlier this week".
The US Congress requires the president to decide periodically whether to certify Iran's compliance with the deal and issue a waiver to allow US sanctions to remain suspended.
"Iran's continued compliance is conditioned on full compliance by the US", Zarif said. He said he would only sign it if an Iranian refusal to allow United Nations inspectors to visit sites triggered an automatic re-imposition of USA sanctions.
"They discussed Iran's repressive actions against protesters and its destabilizing activities in the Middle East", and Gabriel briefed Tillerson on meetings this week among European powers and Iranian representatives, the statement said.