On Saturday, the American missile tracking vessel USNS Invincible and three accompanying vessels were forced to change course because of the approach of Iranian fast-attack boats. It was the Invincible's second encounter with an Iranian naval vessel in a week, following a close approach by an Iranian frigate on Thursday. U.S. Navy officials say that close encounters between American and Iranian assets near the Strait of Hormuz are increasingly common and potentially dangerous.
The attack craft did not respond to radio communications and approached within 600 yards before halting their advance. The encounter forced the Invincible and three accompanying Royal Navy vessels to alter course. Pentagon spokesman Capt. Jeff Davis told media on Monday that such encounters pose the risk of a "miscalculation or an accidental provocation."
The Invincible is one of two missile range instrumentation vessels operated by Military Sealift Command in support of the U.S. Air Force (not Navy). She began her life as a sub-hunting ship, but she was refitted in 2000 with the Air Force's Cobra Gemini dual-band radar for tracking theater ballistic missiles. She lacks the precision and power of larger ICBM-tracking platforms, but she fills an important niche for tracking short-range missile launches. She is normally stationed in the Arabian Sea and the Indian Ocean.
U.S. officials told Fox News on Monday that Iran test-fired two Fateh-110 ballistic missiles on Saturday and Sunday, including at least one launch intended to test an anti-ship variant. The second test successfully struck a floating barge at a range of 155 miles, a targeting capability that Iran's military has reportedly improved by fitting the missiles with a new "active seeker."