Tehran, Iran - Iran on Wednesday said it would target US military bases in the region if President Donald Trump follows through with his threats of war.

Iran and the US have held five rounds of talks since April to thrash out a new nuclear deal to replace the 2015 accord that Trump abandoned during his first term in 2018.

Since returning to office in January, Trump has revived his "maximum pressure" campaign on Tehran, backing nuclear diplomacy but warning of military action if it fails.

"All its bases are within our reach, we have access to them, and without hesitation we will target all of them in the host countries," Iran's Defence Minister Aziz Nasirzadeh said in response to US threats of military action if the talks fail.

Donald Trump Trump moves US personnel from Middle East after Iran's major threat

"God willing, things won't reach that point, and the talks will succeed," the minister said, adding that the US side "will suffer more losses" if it came to conflict.

In an interview published on Wednesday, Trump said he was "less confident" a deal could be reached, in response to a question on whether he believed he could stop Tehran from enriching uranium – a red line for Iran.

"I don't know. I did think so, and I'm getting more and more – less confident about it. They seem to be delaying and I think that's a shame. I am less confident now than I would have been a couple of months ago," he told the New York Post's podcast Pod Force One.

"Something happened to them but I am much less confident of a deal being made... Maybe they don't wanna make a deal, what can I say? And maybe they do. There is nothing final."

The US and its allies have long accused Iran of seeking to acquire nuclear weapons, while it insists the nuclear program is for peaceful purposes.