Originally posted by the Voice of America. Voice of America content is produced by the Voice of America, a United States federal government-sponsored entity, and is in the public domain. US Warship Fires Warning Shot at Iranian Military Vessel by Carla Babb PENTAGON -- A U.S. Navy ship patrolling in the Persian Gulf fired warning shots at an Iranian Revolutionary Guard ship after it got too close to the vessel, a U.S. defense official confirmed to VOA Tuesday. The USS Thunderbird fired "a couple of warning shots" at the Iranian vessel after it came within 140 meters of the U.S. ship at a high rate of speed, according to the official. The shots were used as a last resort after the Iranian ship failed to respond to calls over the radio and sound signals from the American ships, including five blasts from the U.S. Navy ship's whistle, an international symbol for danger. Two ships from the United States Coast Guard were patrolling with the USS Thunderbird during the incident, the defense official told VOA. The defense official called the incident "unsafe and unprofessional." "These sort of unsafe and provocative actions from the Iranians do nothing but needlessly increase the risk for miscalculation," the official told VOA. Last month, an Iranian military vessel trained a laser on an American helicopter that was accompanying three American military ships in the Strait of Hormuz. Commander Bill Urban, the spokesman for the US Navy's Fifth Fleet, said the Iranian vessel came within 730 meters of the USS Batan assault ship.