The helicopter was flying overhead when the Iranians trained a weapon on it, according to a defense official. The Iranians did not fire. The event took place as the helicopter was escorting the aircraft carrier USS Dwight D. Eisenhower on its way out of the Persian Gulf.
Iranian ships regularly approach US Navy vessels in that area of the strait.
In August the USS Squall fired three warning shots into the water after boats belonging to Iran's Revolutionary Guard Corps came within close proximity to American warships.
The US military has expressed its concern regarding what it sees as Iran's provocative naval actions in the gulf.
"If they continue to test us, we are going to respond, and we are going to protect ourselves and our partners," Gen. Joseph Votel, commander of US Central Command, said at a Pentagon news conference in August following the incident with the Squall.
A US defense official told CNN in August that the number of these unsafe incidents had already surpassed the entire amount for 2015.
Votel, the senior US military commander in the Middle East, calculated that "about 90% of these unsafe, unprofessional activities" are by the IRGC navy and not Iran's general navy.
"So this is, in my view, is not about the Iranian people," Votel said. "It's about the Iranian regime and their desire to continue to do these types of things that stoke instability or attempt to stoke instability in the region."
The gulf and narrow Strait of Hormuz are considered key strategic bodies of water given the high volume of commercial oil that is shipped through them.
Iran's chief of staff of the armed forces said Saturday that Tehran might establish naval bases in both Syria and Yemen, according to the semi-official Tasnim news organization.
In October, missiles were fired at the USS Mason off the coast of Yemen. The missiles originated from Houthi-controlled territory and the Houthi rebels are backed by Iran. That attack merited a retaliatory US airstrike against radar installations in the area.