DUBAI, United Arab Emirates >> A U.S. Navy patrol boat fired warning shots today near an Iranian vessel that American sailors said came dangerously close to them during a tense encounter in the Persian Gulf. Iran’s hard-line Revolutionary Guard later blamed the American ship for provoking the incident.

The encounter involving the USS Thunderbolt, a Cyclone-class patrol ship based in Bahrain as part of the U.S. Navy’s 5th Fleet, is the latest confrontation between Iranian vessels and American warships.

The Thunderbolt was taking part in an exercise with American and other coalition vessels in international waters when the Iranian patrol boat approached it, 5th Fleet spokesman Lt. Ian McConnaughey said. The Iranian ship did not respond to radio calls, flares and horn blasts as it came within 150 yards (137 meters) of the Thunderbolt, forcing the U.S. sailors aboard to fire the warning shots, McConnaughey said.

“After the warning shots were fired, the Iranian vessel halted its unsafe approach,” the lieutenant said in a statement, adding that the Iranian vessel created “a risk for collision.” Large ships can’t stop immediately on the water, meaning getting close to each other risks a collision.

Video released by the Navy included a sailor giving a position off the eastern coast of Kuwait as the Iranian vessel sat directly in front of an American warship’s bow. Another video included images of the Iranian ship off the Thunderbolt as its horn blared. The sound of machine gun fire followed.

Iran’s paramilitary Revolutionary Guard instead blamed the Thunderbolt for the incident in a statement, saying the American vessel moved toward one of its patrol boats. It said the Thunderbolt fired into the air “with the intention to provoke and create fear.”

Iran and the U.S. frequently have tense naval encounters in the Persian Gulf, nearly all involving the Revolutionary Guard, a separate force from Iran’s military that answers only to the country’s supreme leader. The U.S. Navy recorded 35 instances of what it describes as “unsafe and/or unprofessional” interactions with Iranians forces in 2016, compared to 23 in 2015.

Of the incidents last year, the worst involved Iranian forces capturing 10 U.S. sailors and holding them overnight. It became a propaganda coup for Iran’s hard-liners, as Iranian state television repeatedly aired footage of the Americans on their knees, their hands on their heads.

Iranian forces view the American presence in the Gulf as a provocation by itself. They in turn have accused the U.S. Navy of unprofessional behavior, especially in the Strait of Hormuz, the mouth of the Persian Gulf through which a third of all oil trade by sea passes.

Associated Press writer Amir Vahdat in Tehran, Iran, contributed to this report.