Strait of Hormuz
Strait of HormuzThinkstock

An Iranian small boat pointed a machine gun at a U.S. Navy helicopter flying off an American aircraft carrier in the Strait of Hormuz on Saturday, two U.S. defense officials told Fox News on Monday.

The two Iranian small boats were spotted approximately nine miles from the aircraft carrier while it was transiting the strait. After spotting the Iranian vessels, the aircraft carrier launched a helicopter, which had been on alert, according to the officials.

The helicopter next flew close to the Iranian small boats, where one of the Iranian vessels pointed its weapon at the helicopter and the pilots reported seeing that the machine gun was loaded, they added.

The U.S. Navy helicopter then returned to USS Eisenhower after the weapon was pointed.

A Navy official called the Iranian behavior “unsafe and unprofessional,” and an “escalating measure.”

The incident is the latest in a series of encounters between Iranian and American forces which have raised tensions in and around the Persian Gulf.

In September, the Navy said Iran had threatened two American maritime patrol aircraft flying over the Strait of Hormuz.

That incident occurred a week after a U.S. Navy patrol ship was forced to change course after a fast attack craft from Iran's Islamic Revolutionary Guard Corps came within 91 meters of it in the central Persian Gulf.

In late August it was revealed that a U.S. Navy coastal patrol ship fired three warning shots at an Iranian ship that sailed within 200 yards in the Northern Persian Gulf.

That incident was one of four close calls in one week involving U.S. and Iranian vessels.

In January, Washington said Iran launched rockets near an American aircraft carrier in the Persian Gulf. While Iran initially denied doing so, footage was later released that proved it had indeed fired on the American carrier.