The concentration of fast attack boats and cruise missiles in and along the Strait of Hormuz and the Persian Gulf by the Islamic Revolutionary Guard Corps Navy, known as the IRGCN, "better allow Iranian naval assets to contribute to and extend Iran's layered defense strategy," the U.S. Office of Naval Intelligence said in the study, dated Fall 2009.
The Revolutionary Guard has gradually expanded its naval capabilities over the years by incorporating Chinese, North Korean and Italian designs and technology, both military and commercial, and it now deploys some of the fastest naval vessels in the Persian Gulf, the study said.
It said the Revolutionary Guard also reportedly wants to develop or acquire "unmanned" naval vessels.
As part of the reorganization, which began in 2007, the Islamic Republic of Iran Navy, or IRIN, has positioned its own naval assets further into the Gulf of Oman, according to the study, first disclosed by the "Secrecy News" website last week.
The assessment of Iran's newfound naval clout comes at a time of growing tension between the Islamic Republic and major powers over the country's nuclear ambitions.
Iran announced plans over the weekend to build 10 new uranium enrichment plants in a major expansion of its atomic program, just two days after the U.N. nuclear watchdog rebuked it for carrying out such work in secret.
The study by the Office of Naval Intelligence cited public statements by Iranian leaders indicating that they would "consider closing or controlling the Strait of Hormuz if provoked, thereby cutting off almost 30 percent of the world's oil supply."
Closing the Strait would cause "tremendous economic damage" to Iran, which would "probably not undertake a closure lightly," the study said, but added: "Disrupting traffic flow or even threatening to do so may be an effective tool for Iran."
Iran's naval reorganization began in 2007 and has included the opening of new bases by the two navies, which had traditionally shared operations in the Caspian Sea, Persian Gulf and the Gulf of Oman.
The Islamic Republic of Iran Navy, IRIN, operates traditional large warships capable of extended patrols and missions in open waters, making it the "natural service" to deploy in the Gulf of Oman to "engage enemy forces as far away from Iranian territory as possible."
The Revolutionary Guard has smaller and faster boats with greater tactical flexibility for asymmetric warfare, the study said.
Favored politically and financially by the Iranian leadership, the Revolutionary Guard has invested in upgraded technology and boat designs from abroad.
These craft may be small, only 17 meters long in some cases, but they carry "serious firepower," including torpedoes and the Iranian-made "Kowsar" antiship cruise missile, the study said.
In addition to using North Korean designs and Chinese technology, the Revolutionary Guard in the late 1990s began purchasing fast boats from Italian speedboat maker Fabio Buzzi and learned how to produce similar models for itself, it said.
Such crafts can reach top speeds of 60-70 knots, giving "the IRGCN some of the fastest naval vessels in the Persian Gulf," the study said.
"Overall, Iran's development program has strengthened its naval capabilities, yielding increases in the country's inventory of small boats, mines, anti-ship cruise missiles, torpedoes, and air defense equipment," the study said.