A veteran confronted Hillary Clinton about her handling of classified information as secretary of state during a presidential forum on Wednesday.

An Air Force and Navy veteran, who said he held "the top secret sensitive compartmentalized information clearance," challenged Clinton's actions as secretary of state live on MSNBC's commander-in-chief forum.

"Had I communicated this information not following prescribed protocols, I would have been prosecuted and imprisoned," said the veteran, identified by MSNBC as a Republican. "Secretary Clinton, how can you expect those such as myself who were and are trusted with America's most sensitive information to have any confidence in your leadership as president when you clearly corrupted our national security?"

"Well I appreciate your concern and also your experience, but let me try to make the distinctions that I think are important for me to answer your question," Clinton responded. "First, as I said to Matt, you know and I know, classified material is designated. ... And what we have here is the use of an unclassified system by hundreds of people in our government to send information that was not marked, there were no headers, there was no statement top secret, secret, or confidential."

She continued, "I communicated about classified material on a wholly separate system. I took it very seriously."

Clinton continued to describe the precautions she took while traveling to prevent visual surveillance of her handling of classified material while on the road.

The Democratic nominee's use of a private server and personal email account dominated Clinton's appearance at the forum led by NBC's Matt Lauer on Wednesday. Her opponent, Donald Trump, appeared second at the event. He has made Clinton's handling of such information a top campaign issue.

Around the time of the exchange, the host of the event seemed eager to move on from the email issue and toward veterans' priorities.