The reason for the mistake was an accidental discharge while the gun was being cleaned. The incident happened as the U.S. destroyer, the U.S.S. Ramage, was in port after retuning from an international exercise in the Baltic Sea. It was preparing to leave later that day. No injuries or damage were reported, the Navy said.
Polish military police boarded the ship to investigate. Navy officials said the crew of the U.S.S. Ramage cooperated fully, and that no U.S. sailors were taken into custody by Polish authorities. There was no immediate word of a U.S. Navy investigation into the incident.
The M240 is a belt-fed, gas-operated medium machine gun firing the 7.62 x 51mm NATO cartridge. The U.S.S. Ramage (shown) is an Arleigh Burke-class Guided Missile Destroyer.