In a phone call that was made public, Trump sought to reassure the governor of Guam about the island's safety, after North Korea announced plans to fire missiles near the Pacific territory.
"Eddie, I have to tell you, you have become extremely famous, all over the world," Trump told the governor.
They are talking about Guam; and they're talking about you, and I think you're going to get tourism.
I can say this, your tourism, you're going to go up like tenfold, with expenditure of no money, so I congratulate you.
It looks beautiful, you know, I'm watching it's such a big story in the news, it just looks like a beautiful place.
Calvo said in response: "We've got 95 per cent occupancy and after all this stuff calms down we're going to have 110 per cent occupancy."
Trump said: "You just went to 110 per cent, I think."
The President also told the governor that the White House was "with you 1,000 per cent".
The recording was put online on the Republican governor's Facebook page and other social media accounts.
Meanwhile, North Korea has said it stands ready to strike Guam, and has warned Trump that America was not an "invulnerable heavenly kingdom".
Yesterday, German Chancellor Angela Merkel called for calm, telling reporters that "an escalation of language certainly doesn't solve any problems".
She said she didn't see a military solution to the conflict, but a need for "enduring work" at the UN Security Council.