"This Post Office scam must stop. Amazon must pay real costs (and taxes) now," President Donald Trump wrote on Twitter. | Evan Vucci/AP Photo Trump escalates attack on Amazon, demands Washington Post register as 'lobbyist'

President Donald Trump continued to needle Amazon on Saturday, claiming the internet commerce giant maintains an advantageous relationship with the U.S Postal Service amounting to a "scam" worth "billions of dollars."

"While we are on the subject, it is reported that the U.S. Post Office will lose $1.50 on average for each package it delivers for Amazon," the president wrote on Twitter. "That amounts to Billions of Dollars. The Failing N.Y. Times reports that ‘the size of the company’s lobbying staff has ballooned.‘”


Trump added that Amazon's lobbying staff does not "include the Fake Washington Post" and that the newspaper, which is owned by billionaire and Amazon CEO Jeff Bezos, is a "lobbyist" and should register accordingly.

"If the P.O. 'increased its parcel rates, Amazon’s shipping costs would rise by $2.6 Billion,’" the president continued. "This Post Office scam must stop. Amazon must pay real costs (and taxes) now!"

The president's tweets came as his motorcade left his Mar-a-Lago estate at about 8:45 a.m. Saturday, heading to his nearby golf course. The president is staying in Florida for the holiday weekend.

Trump's attacks on The Washington Post come as a story about the damage being done to the president's family real-estate and marketing business by porn star Stormy Daniels and special counsel Robert Mueller's probe was leading the paper's website Saturday morning.

The president has often conflated Bezos' dual roles as Post owner and Amazon CEO. The two entities are separate.

The $1.50 figure comes from a Wall Street Journal op-ed, which cited a Citigroup analysis that the Postal Service loses $1.46 on each package it delivers for Amazon. But a Fortune magazine report found that such a subsidy is due to congressional action that limits the postal service's ability to compete with companies like FedEx.

The president also attacked Amazon on Thursday, accusing the company of paying less than its fair share in taxes and abusing the postal service.

Trump later Saturday posted an attack on California Gov. Jerry Brown, whom he has dubbed in the past as "Moonbeam" Brown, tagging Fox News in the tweet.