US President Donald Trump has signed an executive order targeting social media companies amid his row with Twitter.

The social network earlier this week applied fact-check warnings to two of Trump's posts about mail-in voting in November's presidential election.

The president hit back with a post accusing Twitter of interfering in the presidential race.

The details of the executive order signed Thursday are unclear.

Prior to the signing, Trump claimed that a small handful of powerful social media monopolies control the vast portion of all public and private communications in the United States.

He also called for a review of a law that protects Twitter and other social media platforms from being held responsible for content posted by their users.