WASHINGTON - US President Donald Trump said Thursday that the United States has a "massive" naval force heading toward Iran, while suggesting it may not be used as tensions remain high amid Iran's unrest.

"We have a lot of ships going that direction just in case. We have a big flotilla going in that direction. And we'll see what happens," Trump told reporters on Air Force One as he returned from the World Economic Forum in Davos, Switzerland.

"We have an armada. We have a massive fleet heading in that direction, and maybe we won't have to use it. We'll see," Trump added.

The USS Abraham Lincoln, along with three destroyers, was spotted making its way to the Middle East from Asia, according to Tuesday's ship-tracking data.

The USS George H.W. Bush has left Virginia and is at sea in the Atlantic, bound for Europe, said a New York Post report.

Trump reiterated that he prefers to avoid conflict, saying, "I'd rather not see anything happen, but we're watching them very closely."

The president said a planned 25-percent tariff on countries doing business with Iran would take effect "very soon."

Despite his tough rhetoric, including a recent call for regime change in Iran, Trump has said he remains open to negotiations.

"Iran does want to talk, and we'll talk," Trump said during his stay in Davos.