WATCH: Trump gets booed in failed attack on Ted Cruz over unreported bank loans

GOP front runner Donald Trump is accustomed to having adoring supporters pack into stadiums to cheer him -- and occasionally rough up protesters -- on campaign stops. But things seemed to change during Thursday night's debate when Trump launched an attack against his closest rival, Texas Sen. Ted Cruz.

Trump, who notoriously doesn't believe that President Barack Obama is a U.S. citizen, began questioning whether Cruz, who was born in Canada, is eligible to run for president, prompting the rowdy debate audience to boo him. The same happened Saturday in South Carolina, according to the Associated Press.

Trump was speaking to an audience of tea party activists on Saturday when he began talking about Cruz's failure to disclose large bank loans from Goldman Sachs that helped fund his 2012 Senate run.

"You give a campaign contribution to Ted Cruz, you get whatever the hell you want," Trump said. "And he's a very nice guy but you have to get -- right?"

The audience began booing at this point.

"Excuse me, excuse me," Trump said nervously, as the audience continued to boo. "He didn't report his bank loans."

Watch the segment, as posted to YouTube, here: