WATCH: Trump takes racist jab at Obama while promising to 'unite' America at Florida rally

GOP front runner Donald Trump has been under the microscope for refusing to disavow racist terror group the KKK and one of its leaders, David Duke.

On Saturday during a rally in Florida, the real estate mogul made comments about President Barack Obama's race. Trump has been an unapologetic birther, meaning he subscribes to a debunked conspiracy theory that Obama is not an American citizen. The so-called birther movement has been largely written off as a racist attack on the nation's first non-white president.

On Saturday, Trump said, "We have a terrible president who happens to be African-American.”

He then promised that he could unite the country.

Watch Trump's remarks, as posted to YouTube, here: