An Iranian missile fired during a training exercise in the Gulf of Oman struck a support vessel near its target, killing at least 19 sailors and wounding 15 others, Iran's navy confirmed in a statement.
The friendly fire incident happened Sunday near the port of Jask, some 1,270 kilometers (790 miles) southeast of Tehran on the Gulf of Oman, state TV reported Monday.
The missile struck the Konarak, a Hendijan-class support ship, taking part in the exercise.
State television described the missile strike as an accident, saying the Konarak had remained too close to the target. The Konarak had been putting targets out in the water for other ships to fire upon, it said.
Iranian media said the Konarak had been overhauled in 2018 and was able to launch sea missiles. The Dutch-made, 47-meter (155-foot) vessel was in service since 1988 and had capacity of 40 tons. It usually carries a crew of 20 sailors.
Iran regularly holds exercises in the region, which is closed to the strategic Strait of Hormuz, the narrow mouth of the Persian Gulf through which 20% of the world's oil passes. The U.S. Navy's 5th Fleet, which monitors the region, did not immediately respond to a request for comment.
Iranian media rarely report on mishaps during its exercises, signaling the severity of the incident. This incident also comes amid months of heightened tensions between Iran and the U.S. since President Donald Trump unilaterally withdrew from Tehran's nuclear deal with world powers in 2018 and imposed crushing sanctions on the country.