But when Walker asked Gingrich about the event, the candidate quickly shut down the interview.

"His aid[e] gave no preconditions; no topics were off limits. That’s why I was so surprised when, before I had finished asking my first question, that same aid[e] cut the interview short and prompted Secret Service to grab and briefly detain me as the former speaker was led away," Walker writes.

According to Walker, the assistant to Gingrich told him, "You're not asking that. You're done."

While Gingrich has frequently made media criticism a central tenant of his campaign — dismissing questions as irrelevant and unfair — the incident is not likely to help his fading campaign.

On Monday, former presidential candidate Herman Cain — once a top Gingrich surrogate — told WMAL he thought the former House Speaker should exit the race.

"To Newt Gingrich I would say, 'Speaker Gingrich, with all due respect, let's get on with this, OK?' " Cain said. "I even endorsed Newt Gingrich at one point because I thought that he had a shot. Well, not now. He doesn't have a shot."