Iran said it had forced a U.S. warship to turn back from entering the Strait of Hormuz on Monday, but a U.S. official denied a report that it had been struck by Iranian missiles, according to an Axios journalist.

Iran’s navy said it had prevented “American-Zionist” warships entering the Strait of Hormuz area by issuing a “swift and decisive warning.”

Iran’s semi-official Fars news agency said two missiles had hit the warship near the port of Jask at the southern entrance to the strait, where Iran’s navy has a base, but a senior U.S. official immediately denied the report, Axios’ Barak Ravid said.

Reuters could not independently verify the reports.

Iran had warned U.S. forces on Monday not to enter the strategic waterway after President Donald Trump said the United States would “guide out” ships stranded in the Gulf by the U.S.-Israeli war on Iran.