Several media outlets have pointed to White House sources who expect the president to decertify Iran's compliance with the deal, which Trump has called "catastrophic" for the U.S., Israel and the Middle East.
If Trump decertifies the agreement, Congress will have 60 days in which it can reimpose economic sanctions on Iran.
It gave Iran sanctions relief in exchange for curbs on its nuclear program in a bid to prevent it from developing nuclear weapons.
Since the historic deal was signed in Vienna, the International Atomic Energy Agency (IAEA) has repeatedly confirmed the Islamic Republic's compliance with its commitments under the JCPOA, but some other parties, especially the USA, have failed to live up to their undertakings. Iran has always insisted that its nuclear program is for peaceful purposes and denies it has aimed to build an atomic bomb.
"The effect of what the president has done has really been to constrain our freedom of action", said Rep. Adam Schiff, Calif., the ranking Democrat of the House Intelligence Committee, "because steps we might have taken to constrain Iran's malevolent activity will now be viewed through the prism of the president's hostility to the nuclear deal".
"They came up with a plan that protects the things they are concerned about but doesn't recertify, which the president made clear he was not going to do". The US president will say the nuclear deal does not serve US national security interests, contradicting his defence secretary and top generals.More news: Australian woman wrangles shark with bare hands out of pool, video shows
Deutch said the danger of walking away from the agreement is that those expiration dates "would have effectively dropped from a decade to a day" because Iran would be freed of its obligations under the deal. However, "as flawed as the deal is, I believe we must now enforce the hell out of it", and make sure inspectors have better access to possible nuclear sites, he said.
The lifting of sanctions is dependent on Iran restricting its nuclear programme. The International Atomic Energy Agency says Iran is complying with the agreement.
As long as Iran honors the terms of the deal, the European side will do the same, Mogherini and Gabriel added.
European allies have complained that the White House has not presented a plan on how to push back Iranian influence, particularly in Syria, where the Trump administration has insisted it did not want to get involved in the civil war, preferring to focus exclusively on fighting the Islamic State.
These plans are expected to highlight how the United States can work with its allies to counter any threats made by the Iranians.
If the USA chose to reimpose nuclear-related sanctions on Iran, it would be in breach of the JCPOA. Engel, the top Democrat on the Foreign Affairs Committee, said unwinding the agreement would send a unsafe signal to allies and adversaries alike.More news: Palestinian Authority, Hamas Reach Reconciliation Deal After 10-Year Feud
"This is not the way of making deals, not in foreign policy, not in private businesses and I think [US] President [Donald] Trump understands that perfectly well", she said.
JCPOA is a "non-binding political agreement".
The U.S. will need to work with Britain, France and Germany - all parties to the Iran nuclear pact - to fix its flaws and those countries need to know that the U.S.is a reliable partner, according to Engel.
The diplomats "discussed the situation around the JCPOA on Iran's nuclear program approved by the UN Security Council in 2015".
But Mr Trump is under pressure both at home and overseas not to scrap the deal. He had certified it twice before but aides said he was reluctant to do so a third time.More news: Jerry Jones: Dallas Cowboys who don't stand for anthem won't play
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