Following the United States exit, Iran and the remaining parties launched talks to save the accord. But they denied security forces were involved, Iranian news agencies reported.
Hundreds rallied in cities including Tehran, Karaj, Shiraz, and Qom, according to videos posted on social media, to protest against high inflation caused in part by a collapse in the rial currency over fears of the reimposition of crippling sanctions on August 7.
So far, they have not been on the scale of the violent unrest that gripped dozens of towns and cities in December and January.
"The establishment knows they are legitimate but my biggest concern is they will be hijacked by groups inside and outside the country and turn violent".
"People are anxious that if they don't buy things today, they won't be available tomorrow", said Ali, who runs a kitchen store in the bazaar, adding that wholesalers were hoarding new stock while they waited to see how the crisis unfolded.
Trump administration officials also argued that because the US lifted sanctions against Iran as part of the agreement, it in effect stripped Washington of one of its most powerful tools to penalize Tehran.
At least for now, the U.S.is fixated on bringing as much diplomatic and economic pressure to Iran as possible - though it is not clear where things are headed, or if there is an increased risk of conflict.
But many smaller firms are hunting loopholes and counting on protection from European governments who are determined to keep the nuclear deal alive.
Neither one of these summits produced anything of real substance for the United States public.
The administration has said a second batch of sanctions will be revived in November.
He said USA threats are making some Europeans more furious than afraid. We can not guarantee that it is suitable for the visually or hearing impaired.
President Trump earlier this year pulled the US out of the highly-flawed global deal meant to prevent Tehran from developing a nuclear weapon and ordered increased sanctions, as well as threatening penalties for companies from other countries that continue to do business with the terror-sponsoring Islamic regime. They will be entered within 180 days and will affect, in particular, trade, oil and banking sectors Iran.
Trump also praised Russian President Vladimir Putin and appeared to take his word for it that Moscow did not meddle in the US's 2016 election, earning himself a stinging rebuke from his own party and top intelligence experts. Iranian oil sales are a crucial source of hard currency.
Trump's policies are already putting significant pressure on the Iranian economy, although US intelligence suggests they may ultimately rally Iranians against the United States and strengthen Iran's hardline rulers, officials say. Israeli Prime Minister Benjamin Netanyahu praised the president's "strong stance" after years in which the Iranian "regime was pampered by the Obama administration and other world powers".
Trump has proven very generous to U.S. adversaries if they meet in the context of summits, but Iran would have to swallow its pride and some humble pie too if it were to kiss the ring.