US President Donald Trump has decided to up the ante in his dispute with Democratic politicians opposed to his hawkish administration's hostile Iran policy, says author and political scientist Kaveh Afrasiabi.

This week Trump indirectly threatened former Secretary of State John Kerry by suggesting that the veteran Democratic politician had violated US laws by giving political advice to the Islamic Republic.

Kerry has had several talks with Iranian diplomats, advising them to be patient and wait until Trump leaves office.

Kerry, who served during the administration of former President Barack Obama, is a main opponent of Trump, criticizing him for pulling the US out of the Iran nuclear deal titled the Joint Comprehensive Plan of Action (JCPOA).

Afrasiabi said Trump's hostile policies towards Iran had proved to be unpopular among some US politicians, including Kerry, who was an outspoken critic of Trump over his Iran policy.

"The mounting opposition to Trump’s war policy ... begins with John Kerry who has been a vocal supporter of Iran nuclear deal, and in the past has defended [Iran's] Foreign Minister Javad Zarif," he said.

"Trump’s purpose in targeting Kerry is basically to witch-hunt against likes of Kerry, and a number of other Democrats who are opposed to [Trump administration's] Iran policy," he said.

"So the purpose of targeting Kerry is to smear him, neutralize him and people like him, who are in the negotiation team of the United States who have also been vocal of opposing Trump’s policies," he said.

According to the US-based analyst, the Trump administration is edging closer and closer to confrontation with Iran.

On Wednesday, Zarif told reporters that Trump could be lured into direct confrontation with Iran.

Zarif said he believed Trump personally did not want war with Iran.

He insisted, however, Trump could be “lured” into war by hawkish politicians advising him at home and abroad.

“I don’t think he wants war,” Zarif said. “But that doesn’t exclude him being basically lured into one.”

Zarif warned that the hawkish “B-team” ­­comprised of US National Security Adviser John Bolton, Israeli Prime Minister Benjamin Netanyahu, Saudi Crown Prince Mohammed bin Salman and Abu Dhabi Crown Prince Mohammed bin Zayed Al Nahyan could lure Trump into war with Tehran.

“Those who have designed the policies that are being pursued do not simply want a negotiated solution. But let me make it clear that Iran is not seeking confrontation, but will not escape defending itself,” he noted.