John Kerry
John KerryReuters

Former Secretary of State John Kerry on Thursday criticized President Donald Trump's policies, warning that he risks driving Iran towards nuclear proliferation and worsening a standoff with North Korea if he ends the nuclear deal with Iran.

“If you want to negotiate with (North Korean leader) Kim Jong Un, and your goal is to avoid war and try to be able to have a diplomatic resolution, the worst thing you can do is first threaten to destroy his country in the United Nations,” Kerry said in a private lecture delivered at Geneva’s Graduate Institute, according to Reuters.

“And secondly, screw around with the deal that has already been made because the message is don’t make a deal with the United States, they won’t keep their word,” added Kerry, who negotiated the 2015 nuclear deal between Iran and world powers.

His comments come a week after Trump refused to certify that Tehran was in compliance with the deal.

Kerry claimed that the nuclear deal places Iran under tough restraints, including round-the-clock surveillance and tracking every ounce of uranium produced.

“We would notice an uptick in their enrichment, like that,” he said, snapping his fingers.

“And nobody that I know of with common sense can understand what the virtue is in accelerating a confrontation with the possibility that they might decide they want to break out and make it (a nuclear bomb) now instead of 10 or 15 or 25 years from now,” added Kerry, who said that if Iran violated the deal, UN sanctions would snap back into place.

Ending the deal could lead to Iran hiding fissile production facilities “deep in a mountain where we have no insight”, he warned, adding, “So the scenario that Trump opens up by saying ‘let’s get rid of the deal’ is actually proliferation, far more damaging and dangerous.”

Kerry is not the only former Obama administration official to criticize Trump's policy on Iran and North Korea. Kerry's predecessor, Hillary Clinton, warned earlier this week that Trump's threat to pull out of the Iran nuclear accord is "dangerous", suggesting he is undermining the validity of the United States' promises to other nations.

The president's insistence on decertifying the deal, even though evidence has pointed to Iranian compliance, "makes us look foolish and small and plays right into Iranian hands," said Clinton.

"That is bad not just on the merits for this particular situation, but it sends a message across the globe that America's word is not good," she added.

The 2016 Democratic presidential nominee also denounced Trump's language toward North Korea, charging that his verbal aggression has rattled American allies.

"We will now have an arms race — a nuclear arms race in East Asia, warned Clinton, who stressed that a diplomatic solution was preferred and suggested the inflammatory rhetoric played into North Korean leader Kim Jong Un's hands.