Speaking to reporters ahead of a cabinet meeting, he said: "I feel strongly about what I did I'm tired of being taken advantage of.
"It might be total termination, that's a real possibility, some would say that's a greater possibility."
His comments came as the EU announced it was sending its chief diplomat to Washington next month to fight to save an accord that saw Tehran dramatically scale back its nuclear ambitions in return for an end to punishing sanctions.
Trump alarmed allies across the Atlantic with a belligerent speech on Friday in which he stopped short of pulling out of the agreement but warned he could do so at any time, restating his belief the deal was letting Iran off the hook.
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EU ministers have warned that ditching the deal when Iran has repeatedly been certified as keeping up its end of the bargain would send a signal to North Korea that negotiating with the international community is a waste of time.
There is broad support among US lawmakers for fresh pressure on Iran over its continued missile development and subversive activities in the region - factors that Trump says violate the "spirit" of the agreement
Tehran has warned such action would mean Washington had broken its end of the bargain, and thus likely signal the end of their own compliance.