IT HASN’T been the best week for Donald Trump Jr.

The son of the Republican presidential candidate has landed himself in hot water when he appeared to make a Holocaust reference while complaining about the treatment his father has received in the US press compared to Hillary Clinton.

During an interview with Philadelphia-based conservative talk radio host Chris Stigall, the American businessman commented that the media allowed the Democratic candidate to “slide” on every “lie”.

“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. They’ve let her slide on every indiscrepancy, on every lie, on every DNC game trying to get Bernie Sanders out of the thing,” the 38-year-old said.

“I mean, if Republicans were doing that, they’d be warming up the gas chamber right now. It’s a very different system — there’s nothing fair about it,” Trump’s eldest child added.

Gas chambers were used by Nazis in the Holocaust, the genocide of millions of Jews and others during World War II.

In a statement issued Thursday afternoon, the Trump campaign denied that Trump Jr. was referring to the Holocaust, saying he was actually talking about the “gas chamber” used in “capital punishment”.

“The liberal, dishonest media is so quick to attack one of the Trumps that they never let the truth get in the way of a good smear,” senior communications adviser Jason Miller told CNN in a statement.

“Don Jr. was clearly referring to capital punishment to make the case that the media continues to take words out of context in order to serve as the propaganda arm of the Hillary Clinton campaign — something that’s only gotten worse as Trump’s poll numbers have improved.”

The Anti-Defamation League, a prominent Jewish advocacy organisation, called out Trump Jr. on social media to apologise.

.@DonaldJTrumpJr: We hope you understand the sensitivity and hurt of making Holocaust jokes. We hope you retract.https://t.co/jL2ZC9Z8pH — ADL (@ADL_National) September 15, 2016

In another interview Wednesday, Trump Jr. was asked why his father hasn’t released his tax returns as presidential candidates have traditionally done. Instead of backing the campaign’s argument that he is under audit by the IRS, Trump’s son suggested that, quite simply, his dad doesn’t want the scrutiny.

“Because 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 [Trump’s] main message,” he told the Pittsburgh Tribune-Review.

Trump Jr’s poor taste comments come as both his father and rival Clinton face pressure to share more medical information after the Democratic candidate fell ill during a 9/11 ceremony in New York on Sunday morning.

While Clinton released a new health bulletin on Wednesday night, the media-savvy Trump teased the results of his recent physical during the taping of US talk show, The Dr Oz Show, a day before releasing the details to the press.

His longtime personal physician Harold Bornstein wrote a one-page letter detailing Trump’s cholesterol, triglycerides, blood sugar and blood pressure results. He confirmed the 70-year-old “is in excellent physical health”.