Energy Transfer Partners (ETP) , the company backing the controversial Dakota Access Pipeline, has sued Greenpeace International and other environmental groups, claiming they operated a criminal enterprise while protesting the pipeline, the Wall Street Journal reports.

The suit was filed in federal court in North Dakota under the Racketeer Influenced Corrupt Organizations Act, a law historically enacted to prosecute the mafia.

ETP claims Greenpeace ran a "relentless campaign of lies and outright mob thuggery." The suit claims the groups took donations from supporters based on false assertions, threatened ETP's supporters and investors, and even warned to destroy the project with "terrorist threats."

"For decades, Greenpeace has executed its fraudulent, slanderous campaigns against hundreds of companies and industries with virtual impunity, and its tactics have become increasingly aggressive as a result," the lawsuit says.

The legal battle is the latest in several legal challenges facing the 12,000-mile pipeline that became operational in June.

Greenpeace issued this response. "We have not yet been served with a lawsuit from Energy Transfer Partners and have no knowledge of its claims, so it is premature for us to comment. Rest assured, we will fully defend ourselves against legal attacks on our existence."

Shares of ETP were climbing over 2% in afternoon trading on Tuesday. 

More of What's Trending on TheStreet: