Iran's Director of Foreign Affairs says "Trump is 'crazy' and his administration is confused."

A senior Iranian official called Donald Trump a "crazy President" whose threats against Tehran weren't going to work, adding that if the US President wanted to talk, he'll not only have to show some respect, but come up with a consistent message.

"Trump is 'crazy' and his administration is confused", Iran's Director of Foreign Affairs for the country's parliament, Hossein Amir-Abdollahian, told CNN in an interview on Monday.

Mr Hossein's remark comes after Mr Trump in a series of tweets on Sunday asked Iran "never to threaten" the US and warned Tehran that if it wants a fight, it would be "the official end" of the Islamic nation.

"In his mind, Mr Trump thinks he has a gun to Iran's head with sanctions and he is trying to shut down our economy," Amir-Abdollahian said. "This is all in his imagination. Now he wants us to call him? This is a crazy president."

"Within the White House there is a lot of conflicting opinions," Amir-Abdollahian said, pointing to "warmongers" in the West Wing and naming National Security Adviser John Bolton.

"Also, Trump is not quite balanced and stable in his decision making, so we are dealing with a confused White House. Iran receives various signals which show that no one knows who owns the White House."

Amir-Abdollahian added that "Mr Trump's tweets are self-contradictory".

He added that Iran wasn't entirely opposed to talking, it's just a matter of how.

"Mr Trump can discuss talking to Iran through a phone when he does not use the language of threat and force," he told CNN. "He can talk about phoning us when he goes back to the nuclear agreement."

Amir-Abdollahian said that Trump has "got no idea about the culture and mentality of the Iranian people" if he thinks threats will work against Tehran.

Shortly after Mr Hossein's interview, US president Donald Trump doubled down on the mixed messages by denying the US is trying to talk to Tehran at all.

"Fake News put out a typically false statement, without any knowledge that the United States was trying to set up a negotiation with Iran. This is a false report," Mr Trump tweeted on Monday.

"Iran will call us if and when they are ever ready. In the meantime, their economy continues to collapse - very sad for the Iranian people."

Mr Trump added that if Iran called, "We would certainly negotiate, I only want them to call if they're ready."

Iranian Foreign Minister Javad Zarif, in response to Trump's threat said on Monday on Twitter, "Never threaten an Iranian. Try respect; it works."

In recent weeks, the US has ended waivers for Iranian oil imports, announced sanctions on Tehran's non-proliferation activity associated with the 2015 nuclear deal and sent a Navy strike group and bomber into the Persian Gulf as US officials leaked reports that claimed a heightened threat from the country, CNN reported.

In response, Iran announced it would stop fully complying with the nuclear deal.

Earlier Monday, an Iranian energy official announced the country has increased its uranium enrichment fourfold and informed the International Atomic Energy Agency.

US Secretary of State Mike Pompeo, Acting Defence Secretary Patrick Shanahan and Chairman of the Joint Chiefs of Staff Gen. Joseph Dunford are set to brief American senators about the situation with Iran on Tuesday.