The video was later deleted by the campaign and posted later in the day with the footage in question removed.
"The corruption in the Veteran's Administration, the incompetence is beyond," Trump says in the video as the stock footage appears. "We will stop that, we're going to take care of our Wounded Warriors."
The video shows the men wearing the St. George Ribbon -- a military symbol in Russia and once a high honor with the Soviets -- among others.
The Trump campaign declined comment.
It's not the first time the campaign has been asked to explain what seemed to be footage mistakenly used.
Earlier this month, a campaign video showing immigrants crossing a border was actually from the border between Morocco and Spain. Trump defended its use, saying "it's really merely a display of what a dumping ground is going to look like. And that's what our country is becoming very rapidly.”