He also accuses it of “putting many thousands of retailers out of business”.
Mr. Trump added in a tweet that “They …use the U.S postal system as their delivery boy causing tremendous loss to the U.S.
It follows a report on the news website Axios on Wednesday that claimed Mr. Trump wanted to “go after” Amazon.
Amazon shares fell more than 4% on Wednesday.
The Axios report claimed: Mr. Trump’s wealthy friends tell him Amazon is destroying their businesses.
It claimed his real estate buddies tell him that Amazon is killing shopping malls and brick-and-mortar retailers and he agrees.