President Trump personally pressured Postmaster General Megan Brennan to double the charges Amazon and other firms pay to ship packages, a new report said Friday.

Brennan resisted Trump’s demand, explaining “in multiple conversations” that the rates are set in contracts and that any changes would have to be approved by regulators, the Washington Post reported.

She also told Trump that the Amazon AMZN, -4.12% relationship was beneficial for the Postal Service and that many other companies also partner with the service for deliveries.

Despite her arguments, Trump has continued slamming Amazon, whose founder and CEO, Jeff Bezos, owns the Washington Post, whose coverage of Team Trump is often critical — or “fake,” in the words of the president.

Key Words:Trump takes credit for coining the term ‘fake’ — at least in regard to the media

Trump has raged in public and private about Amazon and Bezos.

Trump claims that Amazon is being subsidized by the U.S. Postal Service and has accused the Washington Post of being Amazon’s “chief lobbyist.”

Key Words:Trump tweets dial up attack on Amazon ‘scam’ and the ‘lobbyist’ and ‘fake’ Washington Post

Some administration officials told the paper that several of Trump’s attacks aimed at Amazon came in response to articles in the Post that he didn’t like.

Trump has met with Treasury Secretary Steven Mnuchin, then–National Economic Council Director Gary Cohn and Domestic Policy Council Director Andrew Bremberg to discuss raising Amazon’s rates, the paper reported.

Trump has slammed Amazon and the Post on social media, briefly driving down Amazon’s stock price.

And he has stated that he doesn’t believe the information his advisers and Brennan have shared with him about the Postal Service’s contract with Amazon. “I am right about Amazon costing the United States Post Office massive amounts of money for being their Delivery Boy,” he tweeted on April 3.

“Amazon should pay these costs (plus) and not have them bourn [sic] by the American Taxpayer. Many billions of dollars. P.O. leaders don’t have a clue (or do they?)!”

Market Pulse:Trump is wrong about Amazon’s taxes and USPS relationship, concludes analyst

Still, U.S. Postal Service officials insisted they make money on their arrangement with Amazon.

In January, Postal Service spokesman David Partenheimer wrote an op-ed for the Hill pushing back against calls for it to raise package rates.

“Some of our competitors in the package delivery space would dearly love for the Postal Service to aggressively raise our rates higher than the marketplace can bear — so they could either charge more themselves or siphon away postal customers,” he wrote.

This report originally appeared on NYPost.com.