(Bloomberg)—U.S. President Donald Trump once again unloaded on Amazon.com Inc., tweeting that the company is hurting other retailers and implying that it’s killing industry jobs across the U.S.

Amazon, No. 1 in the Internet Retailer 2017 Top 500, is causing “great damage to tax paying retailers,” Trump said in a Twitter post Wednesday, causing shares in the online retailer to fall as much as 1.2% in early trading.

Amazon is doing great damage to tax paying retailers. Towns, cities and states throughout the U.S. are being hurt – many jobs being lost!

— Donald J. Trump (@realDonaldTrump) August 16, 2017

Trump is losing the support of many company executives, some of whom resigned this week from a council of business leaders to protest the president’s response to the violent demonstrations in Charlottesville, Va. But he has often taken particular aim at Amazon and the Washington Post, owned by Amazon founder Jeff Bezos, for its coverage.

During the presidential campaign, Trump claimed Amazon was a monopoly that he would go after for antitrust violations if he were elected. Amazon takes about 70% of all e-book sales and 30% of all U.S. e-commerce. “Believe me, if I become president, do they have problems. They’re going to have such problems,” Trump said in February 2016. In the U.S. it isn’t illegal to have a large market share.

While it’s unclear what prompted Trump’s tweet, which seems to be taking on two issues—taxes and jobs—The Washington Post ran a scathing editorial about Trump in the paper Wednesday, and there were also pro-tax reform advertisements that ran on early morning talk shows.

It’s often difficult to parse Trump’s tweets, but he seems to be focusing partly on how Amazon’s sales and market share growth is hurting the traditional retail industry. His remarks come amid one of the most tumultuous years in the industry’s history. Bricks-and-mortar chains, especially apparel sellers, are suffering from sluggish mall traffic and an exodus of shoppers to e-commerce.

A rash of chains have filed for bankruptcy this year, including Payless Inc. (No. 364), Gymboree (no. 392) and HHGregg Inc. (No. 233) and RadioShack, No. 590 in the Internet Retailer 2017 Top 1000. And the biggest department-store companies, such as Macy’s Inc. (No. 6), Sears Holdings Corp. (No. 19) and J.C. Penney Co. (No. 33), are shuttering hundreds of locations. The total number of store closings is expected to hit a record in the U.S. this year, with Credit Suisse Group AG analyst Christian Buss estimating that the number could exceed 8,000.

On the other hand, Amazon is hiring rapidly. The online behemoth has pledged to hire more than 100,000 workers by 2018 and has been holding job fairs all over the U.S. In some cases, fired department store workers are ending up at Amazon fulfillment centers.

In his tweet, Trump also hammered Amazon again on tax-related allegations. It’s unclear exactly what he means since the company has been opening distribution centers everywhere and now collects sales tax in each state that has one.

In June, Trump posted a tweet attacking “AmazonWashingtonPost, sometimes referred to as the guardian of Amazon not paying internet taxes.”

In December 2015, Trump also described the Washington Post as a tax shelter that Bezos uses to keep Amazon’s taxes low. Without these arrangements, Trump argued, Amazon’s stock would “crumble like a paper bag.” Bezos actually owns the Washington Post via a holding company separate from Amazon. Amazon did not respond to a request for comment.

Amazon has been battling a number of politicians from both the U.S. and Europe about its stance on tax. In the U.S., Amazon previously fought to avoid having to collect sales taxes for purchases in states where it doesn’t have a physical presence. Now it has a legion of distribution centers and collects sales tax in every state that has one.

The U.S. retailer is currently fighting the European Union over its tax bill, while in March it won a $1.5 billion tax dispute with the IRS.