— -- A Navy ship fired multiple warning shots at an Iranian vessel in the Persian Gulf that came within 150 yards of the U.S. ship, the Navy confirmed.
The Iranian vessel, belonging to the Islamic Revolutionary Guard Corps, approached the USS Thunderbolt at a high speed and ignored warnings from it, including voice communications and sound signals.
"The Iranian vessel did not respond to repeated attempts to establish radio communications as it approached," U.S. Naval Forces Central Command said in a statement. "Thunderbolt then fired warning flares and sounded the internationally recognized danger signal of five short blasts on the ship's whistle, but the Iranian vessel continued inbound."
It wasn't until the warning shots were fired that the Iranian craft halted its approach, the Navy said.
The Navy characterized the encounter, which occurred around 3 p.m. local time Tuesday, as "an unsafe and unprofessional interaction" and said the Iranian boat's actions did not follow internationally recognized "rules of the road ... creating a risk for collision."
The Thunderbolt, a Navy patrol craft, was conducting a coalition exercise in international waters when the Iranian vessel approached, according to the Navy.
While close encounters between U.S. ships and Iranian small craft in the Gulf are common, it's rare for a U.S. ship to fire warning shots. This is the closest that an Iranian vessel has come to a U.S. ship in the Gulf in at least a year.
In January a Navy destroyer, the USS Mahan, fired a burst of warning shots at four Iranian small craft that were approaching a high speed. Those boats got as close as 890 yards. And in August of last year, the USS Squall fired warning shots into the water in front of a speeding Iranian boat to warn the craft that it had come within 200 yards.
In a more recent encounter the Navy deemed "unsafe and unprofessional," an Iranian ship targeted a laser at a U.S. helicopter as it accompanied three Navy ships through the Strait of Hormuz last month.
After that incident, a spokesman for the Navy's 5th Fleet said, "Illuminating helicopters with lasers at night is dangerous, as it creates a navigational hazard that can impair vision and can be disorienting to pilots using night-vision goggles." The closest the Iranian vessel got to those U.S. ships was 800 yards.