Iranian naval forces repeatedly aimed a laser at an American military helicopter during a routine flight in international airspace over the Gulf, the US military said Thursday, according to the AFP news agency.
The helicopter -- an AH-1Z Viper -- is attached to a unit deployed on the USS Bataan amphibious assault ship, which was sent to the region as part of American efforts to deter seizures of commercial tanker ships by Tehran.
Iranian "vessels shone a laser multiple times at the aircraft while in flight" on Wednesday, spokesman Commander Rick Chernitzer said in a statement on Thursday.
"These are not the actions of a professional maritime force. This unsafe, unprofessional, and irresponsible behavior by the Iranian Revolutionary Guard Corps Navy risks US and partner nation lives and needs to cease immediately," Chernitzer added.
The Persian Gulf has been an area of tensions between the US and Iran. The US recently announced it would be beefing up its use of fighter jets around the strategic Strait of Hormuz to protect ships from Iranian seizures.
Later, the Pentagon said that the United States will send additional F-35 and F-16 fighter jets, along with a warship to the Middle East.
The US decided to beef up its presence in the region comes after Iran tried to seize two oil tankers near the strait last week, opening fire on one of them.
Officials have said that, in the past two years, Iran has harassed, attacked or interfered with the navigational rights of 15 internationally flagged commercial vessels.
In late April, Iran seized the Marshall Islands-flagged Advantage Sweet as it traveled in the Gulf of Oman. Six days later, it seized a second ship, the Niovi, a Panama-flagged tanker as it left a dry dock in Dubai.