Donald Trump Jr. speaks at the 2016 Republican National Convention. Alex Wong/Getty Images Donald Trump Jr. alluded to the Holocaust when comparing the media treatment of his father to that of Hillary Clinton.

Speaking with the Philadelphia radio station WPHT on Thursday, the Republican presidential nominee's son argued that the media unfairly under-covered various Clinton controversies, including her use of a private email server while she was secretary of state.

"The media has been her number one surrogate in this. Without the media, this wouldn't even be a contest, but the media has built her up," Trump said.

He added: "They've let her slide on every in-discrepancy, on every lie, on every DNC game trying to get Bernie Sanders out of this thing. If Republicans were doing that, they'd be warming up the gas chamber right now."

The younger Trump's own statements have occasionally raised eyebrows among political observers.

In an interview published in The Pittsburgh Tribune-Review on Wednesday, Trump said that his father continued to refuse to release his tax returns because it would "detract" from his pitch to voters.

"He's got a 12,000-page tax return that would create ... financial auditors out of every person in the country asking questions that would detract from [Donald Trump's] main message," Trump said.