"If the US drops out of the deal now, it won't be very credible in the eyes of those we want to drop nuclear programmes, like North Korea," Russian Foreign Minister Sergej Lavrov said.
The Joint Comprehensive Plan of Action was agreed two years ago between Iran and six powers, including the United States, under then-president Barack Obama.
But his successor, who came to power in January, has labelled the agreement too lenient on Iran and accuses the country of violating it, calling for a renegotiation.
"What kind of example is the leader of North Korea getting?
"He will say, 'even if they give me a deal, what happens when the next president comes to the White House'?" Lavrov said at a conference in the Italian capital.
"I hope there will be no breach of the deal by anyone," he added.
A UN watchdog report in November said Iran remains in compliance with the deal.
Trump has left the accord's fate up to Republican- controlled Congress, giving it 60 days - which run out in mid-December - to decide whether to reimpose sanctions on the Islamic republic.
"The deal is there, Iran is in compliance, it's part of international law, full stop," Lavrov said.
"If it ain't broke don't fix it," he added.
The Russian is not the first to suggest Trump's wavering on the Iran deal could backfire.
French President Emmanuel Macron warned last month that "if you want to stop any relation with Iran regarding nuclear activity, you will create a new North Korea".
(This story has not been edited by Business Standard staff and is auto-generated from a syndicated feed.)