US President Donald Trump claimed an American naval vessel downed an Iranian drone that threatened the ship as it was entering the strategic Strait of Hormuz.

"Despite Trump's baseless and delusional claims, all of (Iran's) drones... have safely returned to their bases," said armed forces spokesman Brigadier General Abolfazl Shekarchi.

"There have been no reports of a confrontation with the American USS Boxer" naval vessel, he added, quoted by Tasnim.

Trump said Thursday the USS Boxer "took defensive action" against an Iranian aircraft as it was "threatening the safety" of the vessel and its crew.

The drone was "immediately destroyed" after it approached within 1,000 yards (914 meters) of the Boxer, Trump said.

Iran's deputy foreign minister Abbas Araghchi denied having lost any drone recently and hinted that the US could have downed their own "by mistake."

The apparent confrontation between the two foes comes after Tehran last month shot down an American surveillance drone it said was flying in its airspace, a claim denied by the United States.