“Three of them maneuvered close to the (US) ship, shadowing her course from a range of about 500 yards (meters),” Davis said.
The Iranian vessels eventually broke away, but one then turned towards the Firebolt and stopped directly in front of it.
“This caused the Firebolt to have to maneuver to avoid collision,” Davis said, noting that the US sailors had attempted to hail the Iranians via radio.
“This is another example of an unsafe and unprofessional interaction we’ve had with the IRGCN.”
Sunday’s encounter is at least the fifth the Pentagon has revealed in the past month, with US military officials repeatedly blasting Tehran for the maritime incidents.
In one incident last month, the USS Squall resorted to firing warning shots from a 50-caliber gun at an Iranian vessel as it approached.
Before that encounter, US defense officials said four Iranian warships in the Strait of Hormuz sped close to two US Navy guided-missile destroyers with their weapons uncovered last month in an “dangerous, harassing situation” that could have led to an escalation.
Video of the incident involving the USS Nitze shows American sailors firing flares and sounding the warship’s horn as the Iranian boats approached. A sailor can be heard saying that the weapons on the Iranian boats were “uncovered, manned.”
The Nitze was accompanied on its mission by the USS Mason, another destroyer.
Navy officials say ships from the US and Iranian navies interacted more than 300 times in 2015 and more than 250 times the first half of this year, with 10 percent of those encounters deemed unsafe and unprofessional.
“Commanding officers of ships are given the inherent right of self-defense, and what we don’t want to have is a situation where, due to miscalculation, that right is invoked when it doesn’t need to be,” Davis said.
In January, the Iranian navy briefly captured the crews of two US patrol boats that had, through a series of blunders, strayed into Iranian territorial waters.
The 10 American sailors were released within 24 hours.