The U.S. military regularly conducts training operations here at home and around the world, but during one of its most recent exercises, thing didn't go quite according to how they were planned as a metal box containing unknown contents has gone missing.

Image source: WSVN-TV

Three choppers were practicing different types of air maneuvers in a joint effort with law enforcement when something apparently just dropped right out of the sky. It happened somewhere over northwest Miami-Dade and Broward Counties late Wednesday night, although it's not clear exactly when or where the box fell, according to the Miami Herald.

All that's known about what's inside the box is that it's full of ammunition and police are not releasing any details. Rather, anyone who might stumble upon the box is being urged not to touch it or otherwise tamper with it. They're being asked to call 911 immediately, WSVN-TV reported.

The specific type of training that was being conducted at the time of the incident was intended to helps the military operate in urban areas, prepare for upcoming deployments and meet certain training certifications.

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