Trump to sign executive order on social-media companies on Thursday

President Donald Trump is poised to sign an executive order on social-media companies Thursday, escalating his war on Twitter Inc., although it remains unclear what it will entail.

A White House spokesperson confirmed the order late Wednesday, a day after Twitter issued its first fact-checking warning label to some of his tweets.

Twitter declined comment. Late Tuesday, a company spokesperson said it issued fact checks because Trump's tweets "contain potentially misleading information about voting processes and have been labeled to provide additional context around mail-in ballots. This decision is in line with the approach we shared earlier this month."

In a series of tweets Wednesday, Trump threatened to "regulate" or even "close" social-media platforms. Legal experts scoffed at the president's ability to moderate f social-media platforms such as Twitter, Facebook Inc. and Snap Inc. .

Twitter shares were down 2.6% in after-hours trading, while Facebook and Snap were down less than 1%.

Speculation centered on whether Trump would push for new legislation or pressure U.S. regulators to sue the companies. Facebook and Google parent Alphabet Inc. are currently under investigation by the Federal Trade Commission and Department of Justice, respectively, for possibly violating antitrust law.