US has not reached out to Iran for talks: Trump

US President Donald Trump on Monday said Washington has not reached out for talks with Iran and that if Tehran wants to negotiate, it will have to take the first step.

"The 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," Trump wrote in a tweet that did not specify what report he was referring to.

"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!" Trump tweeted.

Trump has blown hot and cold over Iran, leading many in Washington to fear he is rushing to conflict, but then indicating that he has no desire to embroil the United States in another distant war.

On Sunday, he upped the temperature with a tweet that warned of "the official end of Iran" should the country attack the United States.

The Trump administration is piling the pressure on Iran by ripping up a hard-fought international deal to steer the country away from its nuclear ambitions and attempting to shut off Iran's badly needed oil exports.

It has also sent an aircraft carrier and bomber planes to the region, citing Iranian threats to US interests.