Iran has developed the capacity to destroy a U.S. warship on less than a minute’s notice, the commander of the Islamic Revolutionary Guards Corps (IRGC) said Tuesday in comments that were met with skepticism by military experts in the West.

In the latest threat that Iran’s hardline military forces have levied at U.S. presence in the region, Navy Rear Admiral Ali Fadavi told semi-official Fars news agency that his forces have been building replicas of U.S. frigates and aircraft carriers for years in order to practice blowing them up. His forces, which patrol the Persian Gulf and the Strait of Hormuz — a major oil supply route — but are separate from the Iranian navy, have the capacity to sink U.S. vessels in that area in 50 seconds, he said.

“We practice the same drills on replica aircraft carriers because sinking and destroying U.S. warships has, is and will be on our agenda,” Fadavi said. “Aircraft carriers are the symbol of America’s military might…so it’s natural that we want to sink the carriers.”

The revelations from the admiral appeared to solve the mystery of satellite imagery published by CNN in March depicting a model of the U.S. Navy’s Nimitz-class nuclear-powered aircraft carrier, complete with planes, docked in Iran’s Gachin shipyard. Iranian media had reported the ship was “part of the décor” for a movie from esteemed director Nader Talabzadeh about the 1988 downing of an Iranian Air plane by the USS Vincennes.

At the time, Iranians bristled at accusations from U.S. intelligence officials that the replica was being built for some propagandistic purpose — perhaps to be blown up as a demonstration of Iranian military prowess. “This issue has turned into a good excuse for another wave of hype against Iran,” said Alef news. “Without any real proof or real basis, Western media have jumped again to paint a more negative picture of Iran.”

But an Iranian newspaper confirmed U.S. suspicions about the model aircraft carrier last month, and on Tuesday Fadavi acknowledged the CNN report, saying only that “the U.S. media and research centers commented on the revelation very simplemindedly. The Americans know nothing.”

A spokesman for the U.S. Navy’s 5th Fleet, which is based across the Gulf in Bahrain, dismissed Fadavi’s threats. "Whatever Iran hopes to do with the mock-up, it is likely to have zero impact on U.S. Navy operations in the Gulf," Commander Jason Salata told The Associated Press on Tuesday.

"Firing weapons at a stationary structure floating on pontoons is not a realistic representation of having the capability to target a 100,000-ton warship ... maneuvering at speeds in excess of 30 knots," he said.

The Revolutionary Guard’s naval forces do not fall under the purview of Iran’s moderate president, Hassan Rouhani, who has taken steps toward rapprochement with the U.S. and has even begun to scale back Iran's nuclear capacity under a deal struck with Western powers. The IRGC and other conservative powers in Iran have largely condemned these steps and persist in their threats against U.S. assets in the region.

Earlier this year, an Iranian commander said Iran would advance naval vessels towards U.S. maritime borders in response to a growing U.S. presence in the Gulf — a threat that was roundly dismissed by the Pentagon on grounds Iran could not afford to risk provoking the U.S.

Iran mined and fired on U.S. warships in the Persian Gulf during the 1987-88 Iran-Iraq War but most military analysts are hard-pressed to conceive of any scenario today where an Iranian act of aggression would not be met by severe reprisal from the vastly superior U.S. military.

“The ability to start something you cannot finish is no measure of military capability,” said Anthony Cordesman, the Arleigh A. Burke chair in strategy at the Center for Strategic and International Studies and a former NATO and Department of Defense official.

Fadavi on Tuesday said that every U.S. warship ferrying through the Strait of Hormuz is contacted by IRGC Naval forces and queried about its identity, purpose, and destination. If they “decline to respond, they will come to realize right away that a large number of our vessels have surrounded them and/or our missiles are locked on them,” Fadavi said.

But given Iran's inferior arsenal, these threats are more readily interpreted as politically motivated, said Cordesman.

“I understand the internal dynamics and the effort to keep up pressure on the U.S. and what the IRGC views as the soft line of the Iranian leadership," he said, "but they cannot possibly expect to be taken seriously here.”