THE US navy has fired warning shots and flares at Iranian speedboats after they refused to slow down in the Strait of Hormuz, defence officials said.

The USS Mahan established radio communication with the four vessels - of Iran's Islamic Revolutionary Guard Corps - but they did not respond to requests to slow down and continued asking the destroyer questions, they said.

1 The USS Mahan (pictured) fired three warning shots and flares at the Iranian boats, officials said Credit: Getty Images

The two officials, speaking on the condition of anonymity, said the ship fired three warning flares and a U.S. Navy helicopter also dropped a smoke float before the warning shots were fired.

The Iranian vessels came within 800 metres of the Mahan, which was escorting two other U.S. military ships, they said.

The IRGC was not immediately available for comment.

RELATED STORIES Exclusive alarming navy cuts Royal Navy ordered sailors to patrol base for blazes - because they were too skint to afford fire alarms IN AND OUTAGE Iran plan to ban internet porn accidentally sparks a bizarre worldwide smut blackout Graphic Warning END OF A TYRANT? Syrian president Bashar al-Assad reveals peace talks could lead to him QUITTING NUKE NIGHTMARE Chilling photos obtained by Israel prove Russia has nuclear-capable missiles in Syria FLIGHT OR FIGHT Is it safe to travel to Turkey? Latest travel advice for British people

The incident comes as President-elect Donald Trump is about to take office on January 20.

In September, Trump vowed that any Iranian vessels that harass the U.S. Navy in the Gulf would be "shot out of the water."

One official said similar incidents occur occasionally. Most recently in August, another U.S. Navy ship fired warning shots towards an Iranian fast-attack craft that approached two U.S. ships.

The official added that the warning shots were just one of seven interactions the Mahan had with Iranian vessels over the weekend, but the others were judged to be safe.

We pay for your stories! Do you have a story for The Sun Online news team? Email us at tips@the-sun.co.uk or call 0207 782 4368.