A newly developed United States Army missile struck a sports hall and school in southern Iran during the early phase of the United States and Israeli war with Iran, according to weapons experts and visual analysis. Iranian officials said the strike and others nearby killed at least 21 people, including young girls who were playing volleyball. The weapon, known as the Precision Strike Missile, has only recently moved beyond prototype testing and remains shrouded in secrecy.

The missile was developed after the collapse of a 2019 arms control treaty that had previously banned certain ground-launched missiles. It is intended to replace an older Army missile system from the 1980s and is expected to have more than double its predecessor’s range. Lockheed Martin manufactures the missile in Arkansas, but neither the company nor the Army has disclosed how many have been produced.

The Defense Department has invested billions of dollars in the program, signaling its importance to future war planning. The missile has undergone more than a dozen test launches in New Mexico and California and is fired from mobile launch vehicles that can quickly relocate after shooting. During the current conflict, the missiles have reportedly been launched from outside the reach of Iran’s air defenses, though the exact launch locations have not been confirmed.