Donald Trump has launched a frontal assault on Amazon.com, the world’s biggest online retailer, saying it has “a huge antitrust problem”.

In a television interview, the presumptive Republican nominee for the presidential race also said Amazon chief executive Jeff Bezos, who owns the Washington Post, was using the newspaper to influence politicians in order to help his company on taxes.

“This [Washington Post] is owned as a toy by Jeff Bezos, who controls Amazon,” Trump told Fox News. “Amazon is getting away with murder tax-wise. He’s using the Washington Post for power so that the politicians in Washington don’t tax Amazon like they should be taxed,.”

“He’s using the Washington Post ... for political purposes to save Amazon in terms of taxes and in terms of antitrust,” Trump said, referring to the process whereby large US companies can be investigated for anti-competitive behaviour.

“He thinks I’ll go after him for antitrust. Because he’s got a huge antitrust problem because he’s controlling so much, Amazon is controlling so much of what they are doing,” Trump said.

“The whole system is rigged ... whether it’s Hillary [Clinton] or Bezos.”

Trump’s comments appeared to be at least partly in response to the prospect of the Washington Post investigating the mogul’s real estate business.

“We’re going to do a book, we’re doing articles about every phase of his life,” Woodward told the National Association of Realtors convention on Wednesday.

Amazon did not immediately respond to a request for comment.

