That the Iranian Revolutionary Guards Corps coast guard would play chicken with the US Navy is not that surprising. Enemies at sea often taunt one another, and I think there were similar feints by Soviet subs in the old days. (A kind reader pointed out that it even happened more recently with China.)
What is harder to understand is the Iranian government explanation, which was that the IRGC did not recognize the US naval ships as such. That isn’t plausible, and besides, what other naval ships would the IRGC have a problem with?
It is the kind of explanation you would give when your nerdy crazy second cousin threatened to beat up a guest twice his size at your cocktail party. I.e., I don’t think the incident was ordered from Tehran, but was some gung-ho local IRGC commander who’d been at sea way too long. I presume they thought the US was in Iranian waters (and the Iranians claim more offshore territory than the standard in international law).
Supreme Jurisprudent Ali Khamenei recently said that while it wasn’t desirable right at the moment, Iranian diplomatic relations with the US in the future were not out of the question. So if anything the top leadership has been trying to ratchet down the tensions.
Here are the most recent entries from the Iranian press culled by the USG Open Source Center on the IRGC naval forces:
‘ IRGC Navy Conducts Final Stages of Persian Gulf Exercises (19 December) – The second and third stages of the Iranian Navy exercise “Courage 86” was carried out over an area of 7,000 nautical miles in the Persian Gulf. An IRGC naval commander, Brig. Gen. Ali Razmjoo, said that the second exercise included pre-emptive defensive and psychological operations, mine-laying operations, night-time tracking of vessels, and deploying frogmen from helicopters into the sea. The third stage included chemical defense, shooting targets at sea, intercepting vessels, and capturing hypothetical targets. Razmjoo said several hundred vessels, missile launchers, destroyers, and mine layers have been involved in a series of IRGC naval exercises in an area between northern Bushehr Province and Asalouyeh over a four-day period (IRNA).Iran Kicks Off War Games in 7,000-Mile Persian Gulf Area (18 December) – Designed to ensure it can protect the nation’s territorial waters, islands, and coastlines, as well as neighboring countries, from foreign threats, Iran began four days of war games in the Persian Gulf on 18 December. According to Press TV, the war games will be held in three stages in an area that encompasses northern parts of Iran’s coastal province of Bushehr and the southern region of Aslouyeh. The war games will cover 7,000 square miles and employ hundreds of vessels and divers (Fars News Agency). ‘
The US says it won’t protest the incident, which means that they concur it wasn’t an intentional provocation from Tehran.