Four vessels from Iran's Islamic Revolutionary Guard Corps (IRGC) "harassed" a U.S. destroyer on Tuesday by carrying out a "high speed intercept" in the vicinity of the Strait of Hormuz, a U.S. defense official said on Wednesday. 

The official, speaking on the condition of anonymity, said two of the Iranian vessels came within 300 yards of the USS Nitze in an incident that was "unsafe and unprofessional."

"The Iranian high rate of closure...created a dangerous, harassing situation that could have led to further escalation including additional defensive measures by Nitze," the official said.

The IRGC, the Islamic Republic's praetorian guard, is suspicious of U.S. military activity near Iran's borders. The Guards operate land and naval units separate from the regular armed forces and stage frequent war games in the Gulf, which separates Iran from its regional rival Saudi Arabia and a U.S. naval base in Bahrain.

In January, 10 U.S. sailors, who were aboard two patrol craft, were detained by the IRGC when they inadvertently entered Iranian territorial waters. They were released the next day after being held for about 15 hours.

The USS Nitze had to alter course in order to increase its distance from the Iranian vessels, the official said. The official said the incident could have led to a diplomat protest, but the United States does not have diplomatic relations with Iran.