NEW YORK (Reuters) - U.S. President Donald Trump’s re-election campaign sued CNN for libel on Friday, over an opinion piece that said the campaign had left open the possibility of seeking Russia’s help in the 2020 election.

FILE PHOTO: U.S. President Donald Trump exits Air Force One after returning from Pennsylvania to Joint Base Andrews in Maryland, U.S., March 5, 2020. REUTERS/Leah Millis

The lawsuit filed in the U.S. District Court in Atlanta was the campaign’s third in 10 days accusing major media outlets of libel, following cases against The New York Times and the Washington Post.

All three lawsuits focused on opinion pieces published in 2019 that, according to the campaign, suggested it has had improper ties with Russia.

CNN had no immediate comment. A person familiar with the matter said CNN had yet to review the lawsuit.

Trump has throughout his presidency battled news media he believes demonstrate bias against him. The Republican president often brands CNN, a unit of AT&T Inc as “fake news.”

Legal experts have said the libel lawsuits might be tough to win because the law affords broad protection to opinion writers who express their views about public officials like Trump.

Friday’s lawsuit objected to a statement in a June 13, 2019 opinion piece by Larry Noble, a CNN contributor and former general counsel of the Federal Election Commission.

After referring to Special Counsel Robert Mueller’s report on Russian interference in the 2016 U.S. election. Noble wrote: “The Trump campaign assessed the potential risks and benefits of again seeking Russia’s help in 2020 and has decided to leave that option on the table.”

The campaign said it has “repeatedly and openly disclaimed any intention to seek Russian involvement in the 2020 election,” and has never made statements suggesting otherwise.

It also said CNN was “well aware” that Noble’s statement was untrue when published, and the piece reflected its “systematic pattern of bias” against the campaign. The campaign used identical language in the Times and Post lawsuits.

Noble’s piece was titled “Soliciting dirt on your opponents from a foreign government is a crime. Mueller should have charged Trump campaign officials with it.”

Trump’s battles with CNN have included the White House’s brief revocation in November 2018 of correspondent Jim Acosta’s credentials, after Acosta questioned him about Russia and about a migrant caravan traveling through Mexico.

The campaign is represented by Charles Harder, who is also known for suing Gawker on behalf of Hulk Hogan, after the news website published a video of the former professional wrestler in a sexual encounter.

Hogan won a $140 million judgment that bankrupted Gawker. He later settled for $31 million.