WATCH: Bernie Sanders Calls Trump's Reaction to Obama 'non-American Muslim' Question 'A Disgrace'

Democratic presidential candidate points out Trump was among leading figures in birther movement and said he hoped Trump would have 'maybe learned something from that.'

Democratic presidential candidate Bernie Sanders on Friday blasted Republican frontrunner Donald Trump for his refusal to correct a man who called President Barack Obama a non-American Muslim.

Speaking on CBS This Morning, Sanders said “I think it’s a disgrace to again question whether or not the president of the United States was born in this country, or whether he’s a Christian."

The event in question occured at a Trump town hall event in Rochester, New Hampshire. The first man Trump called on said "we have a problem in this country. It's called Muslims. We know our current president is one. You know he's not even an American," the man said to a smirking Trump.

The man continued asking about "Muslim training camps" in America and asked "when can we get rid of it?" to which Trump replied, "We're going to be looking at a lot of different things. And you know a lot of people are saying that, and a lot of people are saying that bad things are happening out there."

"I thought we were beyond that. It's an outrage," Sanders said. Sanders noted that Trump was one of the leaders of the birther movement that claimed Obama wasn't born in the U.S. and said that he had "hoped he would have maybe learned something" from that experience.

Earlier this week, U.S. Vice President Joe Biden slammed Trump for selling a "sick message" about immigrants in America based on xenophobia, and fellow Republican presidential candidate Carly Fiorina attacked Trump for his chauvinistic comments on her appearance.