Kristine Coratti Kelly, vice president of communications at the Post, said it was “disappointing to see the president's campaign committee resorting to these types of tactics and we will vigorously defend this case.” Trump has chafed at media scrutiny and repeatedly lashed out against the newspaper and its owner, Amazon founder Jeff Bezos.
The lawsuit, filed US District in Washington, came a week after the campaign sued The New York Times for defamation over an op-ed that claimed a quid pro quo between Trump and Russia.
The American Civil Liberties Union called both lawsuits meritless.
“Anyone who cares about the First Amendment should be troubled by the Trump campaign's repeated attempts to punish and intimidate the president's critics,” said Brian Hauss, staff attorney for the ACLU's Speech, Privacy, and Technology Project.
He spoke in response to the libel suit against the Post.