A U.S. Navy patrol boat fired warning shots toward an Iranian naval ship during a "tense encounter" in the Persian Gulf on Tuesday, according to an American defense official.
The U.S. Cyclone-class patrol ship, the USS Thunderbolt, was at the time involved in an exercise with American and partner vessels in the Persian Gulf, the Associated Press reported.
An American defense official told the AP that the Iranian naval vessel came within 150 yards of the Thunderbolt. After the Iranian vessel did not respond to radio calls, flares, or warning sirens, U.S. sailors were forced to fire warning shots.
Tense naval encounters are not uncommon between Iranian and U.S. forces in the Gulf: Ten U.S. sailors were detained by the Iranian military in January 2016. The U.S. Navy condemned the actions taken by Iranian forces, calling them "outrageous and unacceptable," and has since taken significant steps to prevent future incidents.
The tension surrounding U.S.-Iranian relations is continuing to rise as Iran seeks to build up its military capabilities and the United States moves to increase sanctions.
On April 26, the U.S. Navy confirmed that a U.S. guided-missile destroyer fired a warning flare toward an Iranian Revolutionary Guard vessel. The Iranian ship came within 1,100 yards of the USS Mahan, closing the distance even after the U.S. ship maneuvered to open the distance.
On July 12, regional reports indicated that Iran, with the support of Russia and North Korea, has been building new long-range ballistic missiles at a Syrian weapons factory.
On July 17, the Trump administration announced initial plans to increase the pressure on Iran with a "slew of new sanctions."
Iranian authorities did not immediately report the incident Tuesday.