Iran's Revolutionary Guard commander Gen. Hossein Salami attends a meeting in Tehran. Iran's Revolutionary Guard shot down a US drone amid heightened tensions between Tehran and Washington over its collapsing nuclear deal with world powers, American and Iranian officials said, while disputing the circumstances of the incident. File picture: Sepahnews via AP
Washington - The Pentagon confirmed Thursday that Iranian forces shot down a US naval surveillance drone but insisted the aircraft was in international air space, not that of Iran.

The BAMS-D drone was downed by an Iranian surface-to-air missile system while flying in international airspace over the Strait of Hormuz, a US Central Command spokesman, Navy Captain Bill Urban, said in a statement. He said it happened at 2335 GMT Wednesday. 

"Iranian reports that the aircraft was over Iran are false," he added. "This was an unprovoked attack on a US surveillance asset in international airspace."

Relations between Iran and the US have been since the superpower accused Tehran of being behind attacks on two tankers in the Gulf of Oman last week.

US President Donald Trump issued a stern warning to ran following the release of a US Navy video purportedly showing an Iranian vessel removing an unexploded mine from one of the tankers.

"Iran did do it and you know they did it because you saw the boat," he said, adding that the limpet mine had "Iran written all over it".

Trump warned that his administration does not "take it lightly."