Iranian Foreign Minister
In an interview published Saturday by Britain's Guardian newspaper, Zarif said Iran would develop much more advanced nuclear technology -- though not for weapons purposes -- if Europe followed the United States in returning to a sanctions regime.
"Europe should lead," he said during an interview in New York.
The deal, agreed in 2015 between Iran and six world powers -- the United States, China, Russia, France, Britain and Germany -- lifts economic sanctions put in place in 2005 in exchange for curbs to Tehran's nuclear programme.
The International Atomic Energy Agency (IAEA) is responsible for verifying that Iran meets the terms of the agreement.
US President Donald Trump has attacked the deal on numerous occasions, vowing to tear it up.
On October 15, Trump is due to testify to Congress whether Tehran is complying with the deal and whether it remains in the United States' interests to stick by it.
If he decides it is not, it could open the way for US lawmakers to reimpose sanctions, leading to the potential collapse of the agreement.
"I think he has made a policy of being unpredictable, and now he's turning that into being unreliable as well," Zarif said.
"My assumption and guess is that he will not certify and then will allow Congress to take the decision."
He said that if the United States scuppers the deal, the decision would prove counter-productive.
"The deal allowed Iran to continue its research and development. So we have improved our technological base," he said.
"If we decide to walk away from the deal we would be walking away with better technology. It will always be peaceful... but we will not observe the limitations that were agreed on as part of the bargain."
Zarif said "walking away" was one of the options being considered by Tehran.
"If Europe and Japan and Russia and China decided to go along with the United States, then I think that will be the end of the deal," he said.
Washington on Thursday pressed for the IAEA to carry out more nuclear inspections in Iran, warning that failure to do so would make the nuclear deal with Tehran "an empty promise".