The Wall Street Journal, citing a U.S. official, reported that U.S. forces early Tuesday fired on a Panama-flagged vessel that intended to pass through the blockade of ports against the Islamic Republic.

The U.S. official said the ship’s crew ignored warnings from U.S. forces tasked with enforcing the naval blockade of Iran’s ports, and after that, a U.S. military helicopter fired at the ship’s helm.

The incident occurred before dawn on Tuesday, and no immediate report of casualties was released. According to the U.S. official, after the attack, it appeared the vessel was trying to transfer its crew to another non-military craft.

The maritime security company Vanguard had also previously reported that the container ship “Vela Nova,” flying the Panama flag, while traveling west in the Arabian Sea and at a distance of about 71 nautical miles from the coasts of Pakistan, was targeted by a missile fired from a helicopter.

Vanguard said: “The missile struck the ship and caused a fire that was then contained.” According to the company, all 17 crew members have been accounted for.