Iranian vessels 'harassed' US destroyer, Pentagon says

On Tuesday, the USS Nitze, an American destroyer operating in the Strait of Hormuz, had a close encounter with four Iranian vessels.

Despite multiple warnings, the Iranian ships closed to within 300 yards of the US destroyer before leaving. The antagonistic encounter is the latest in a series of similar incidents involving Iranian forces over the past several years.

Tuesday's incident could have gone much worse.

An anonymous US defense official told Reuters that the four vessels "harassed" the Nitze by "conducting a high speed intercept" of the destroyer. The American vessel reportedly tried to warn off the ships via radio 12 times, but each time received no response. The Nitze was forced to change course to maintain its distance and shot off flares to warn against coming any closer before the ships finally moved off. The official called the encounter "unsafe and unprofessional."

The Nitze had been conducting a routine transit with the USS Mason across the strait, an important passage for oil transport from Saudi Arabia, a major US ally in the region. The strait is situated between Iran and the United Arab Emirates.

The encounter seems to have been deliberately antagonistic, ignoring the 1972 Convention on the International Regulations for Preventing Collisions at Sea that govern proximity and speed of ships in international waters, according to CNN. The disregard for safety regulations and the lack of formal diplomatic relations with Iran created an environment that could have pushed the Nitze into using force to defend itself, causing the situation to escalate into a violent exchange.

As The Christian Science Monitor has previously reported, these kinds of antagonistic encounters with Iran are not uncommon. An incident in January involved an American crew captured and held at gunpoint after inadvertently crossing into Iranian waters. Later that same month, Iran reported that it had flown a drone over a US aircraft carrier.

The Iranian vessels were under the command of the Islamic Revolutionary Guard Corps (IRGC), which is a branch of the country's armed forces. However, the IRGC is not Iran's regular military. While the Army protects the nation's borders and maintains order within the county, the IRGC's main task is to protect the country's Islamic system, according to the BBC. As such, it is generally more antagonistic toward the United States and Western forces, despite last year's nuclear accord between Iran and six other countries, including the US.

"For four decades the Revolutionary Guard have been told that America is the greatest threat to the Islamic Revolution," Karim Sadjadpour, an Iran expert at the Carnegie Endowment for International Peace, told Reuters. "This institutional culture hasn’t changed after the nuclear deal."

The IRGC was also responsible for the January incident when the American crew was captured for crossing into Iranian waters.

According to Tasnim News Agency, a privately owned Iranian news organization, Iranian defense minister Brigadier General Hossein Dehqan warned away any vessel intruding in Iranian waters during a press conference on Thursday, after reports of the Nitze encounter had a begun to come to light.

However, it is still unknown whether the antagonizing encounter was sanctioned by officials in Tehran, or simply the work of four IRGC commanders.