The two ships were just a few hundred yards apart on July 25 when Iranian crewmembers pointed what are believed to be on-deck machine guns at the warship and the U.S. military helicopter that had just landed on that coalition ship's deck, the Defense official said.

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However, the coalition warship and helicopter crew quickly noticed there was a cameraman standing right behind one of the Iranian gunners.

"Were they just trying to get cool pictures pointing at us? Were they making a propaganda film? Was some guy taking pictures to send to his girlfriend? We don't know," the Defense official said.