US president says although the pilots were rescued, Washington 'must, of necessity, respond to this attack'.

President Donald Trump has accused Iran of shooting down a United States military helicopter over the Strait of Hormuz, saying that he will respond to the attack.

“I have just been informed by our Great Military that last night the Iranians shot down one of our highly sophisticated Apache Helicopters while patrolling over the Strait of Hormuz,” Trump wrote in a social media post on Tuesday.

“There were two pilots involved, both are safe and uninjured. Nevertheless, the United States must, of necessity, respond to this attack.”