TOKYO — One of the tankers that were attacked in the Gulf of Oman was struck by a flying object, the ship’s Japanese operator said on Friday, expressing doubt that a mine had been attached to its hull.

Secretary of State Mike Pompeo said on Thursday that American intelligence agencies had concluded that Tehran was behind the disabling of two tankers in the Gulf of Oman, a vital conduit for much of the world’s oil. Iranian officials denied any involvement in the events, which have escalated tensions in the region.

[Read: U.S. Says Video Shows Iran Was Involved]

In an interview broadcast on Friday by “Fox & Friends,” President Trump directly accused Tehran, saying, “Iran did do it.”

“You saw the boat,” he said. “It has Iran written all over it.” Mr. Trump added: “They didn’t want the evidence left behind. They don’t know that we have things that we can detect in the dark that work very well. We have that. It was them that did it.”