The Barstool Sports founder David Portnoy said in a string of tweets about unionizing the sports site that he would fire employees.

His threats stem from Bill Simmons' sports site, The Ringer, announcing a union on Monday.

The National Labor Relations Board specifies that it is illegal for employers to discourage union activities.

Rep. Alexandria Ocasio-Cortez of New York retweeted Portnoy's tweet and said his comments were "likely breaking the law." Portnoy then challenged her to a debate.

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The Barstool Sports founder Dave Portnoy said he would fire employees who contact a reporter or a lawyer about unionizing.

On Monday, Portnoy tweeted about Bill Simmons' sports site, The Ringer, forming a union backed by the Writers Guild of America East with a link to a 2015 Barstool story about Gawker Media unionizing.

"I hope and I pray that Barstool employees try to unionize," Portnoy wrote in the four-year-old blog post. "I can't tell you how much I want them to unionize. Just so I can smash their little union to smithereens. Nothing would please me more than to break it into a million little pieces."

Over the past few years, employees at major newsrooms like BuzzFeed News, Vice Media, Vox Media, and New York magazine have formed unions seeking better working conditions in a turbulent industry.

Read more: BuzzFeed cut 15% of its staff, and some critics are now taking shots at CEO Jonah Peretti's strategy

On Tuesday, Portnoy responded to a string of tweets about the post and threatened to fire employees.

Portnoy responded to a tweet by Rafi Letzter, a staff writer at Live Science, that encouraged Barstool employees to send him a private message to talk about the unionization process by saying he would fire any employee who contacted Letzter "on the spot."

[Letzter worked at Business Insider from 2015 to 2017 as a science reporter.]

Barstool Sports did not respond to a request for comment about Portnoy's tweets or possible unionization plans.

Portnoy also threatened to sue employees who contacted Matthew Weir, an attorney at the law firm Holwell Shuster & Goldberg LLC who had tweeted that Barstool employees could contact him for pro bono help.

Rep. Alexandria Ocasio-Cortez of New York then tweeted that Portnoy was "likely breaking the law" with his comments threatening to fire employees.

The National Labor Relations Board specifies that it is illegal for employers to discourage union activities.

Portnoy responded and challenged Ocasio-Cortez to a debate.

He also responded to a string of tweets, including one expressing hope that Barstool does unionize.

Portnoy, known for making controversial comments, in March apologized for a "moronic" spat with a comedian.