Last Thursday, an American surveillance ship, the USNS Invincible, had a run-in with Iranian Naval frigate that U.S. officials characterized as “unprofessional.”  The ship was then harassed by Iranian vessels once again on Saturday, forcing it and the British ships it was accompanied by to change course to avoid a collision.

The USNS Invincible is an unarmed surveillance ship equipped with sonar, designed to monitor submarine activity as well as radar to track surface missile launches, similar to the Russian vessel seen off the coast of the United States in recent weeks.  Last Thursday, an Iranian naval frigate came within a hundred and fifty yards of the American ship in the Gulf of Oman, just south of the strategic Strait of Hormuz.  The interaction between the two vessels was deemed “unprofessional” but not unsafe, as the frigate maintained a course that was parallel to that of the Invincible and didn’t pose a direct threat to the safety of those on board.

The USNS Invincible courtesy of the US Navy

Iranian fast-attack boats set their sights on the Invincible once again on Saturday, this time however, their conduct has been labeled both “unprofessional” and “unsafe” as the boats positioned themselves directly in the path of the larger American vessel, as well as three British Navy ships traveling in formation with the Invincible.

The four ships were forced to alter their course in order to avoid a collision with the Iranian crafts.  The fast attack boats were manned by members of Iran’s elite Revolutionary Guard.