Washington — US President Donald Trump said Wednesday he hopes the US does not go to war with Iran but if it did, America's use of force would be overwhelming.

In an interview on Fox Business News, Trump was asked if America is going to go to war with Iran.

"Well, I hope we don't but we're in a very strong position if something should happen. We're in a very strong position. It wouldn't last very long, I can tell you that. And I'm not talking boots on the ground," Trump said amid acute tensions between the two countries.

In the current crisis with Iran, exacerbated by its downing of an unmanned US spy drone last week, Trump has at turns sounded tough or conciliatory -- talking up US military might and saying all options are on the table, or offering Tehran talks on renegotiating the multi-party nuclear deal that Trump withdrew from last year.

The comments come just days after Trump cancelled air strikes minutes before impact, with allies warning that the increase in tensions since the United States pulled out of a nuclear pact with Iran last year could accidentally lead to war.

Iran suggested it was just one day from breaching a threshold in the agreement that limited its stockpile of uranium stocks, a move that would put pressure on European countries that have tried to remain neutral to pick sides.

The rhetoric between the sides has heated up, with Trump this week threatening "obliteration" of Iran after Iranian President Hassan Rohani on Tuesday said the White House's actions were "mentally retarded."

"I don't think their leadership is smart," Trump told Fox Business Network on Wednesday.

"Iran is going down the tubes," he added, citing biting US sanctions as well as unrest in the country and other economic pressures. — Agencies