"The Russia hoax continues, now it's ads on Facebook," Trump wrote on Twitter. "What about the totally biased and dishonest Media coverage in favor of Crooked Hillary," referring to Hillary Clinton, his rival in the 2016 presidential campaign.

Earlier this month, Facebook said an internal review had shown that an operation likely based in Russia spent $100,000 on 3,000 Facebook ads promoting divisive messages in the months before and after the 2016 U.S. presidential election.

The company initially declined to turn over details on the ads to Congress but said on Thursday it would do so, making a concession to U.S. lawmakers who have threatened to regulate the world's largest social network over ads that run during election campaigns.

Chief Executive Mark Zuckerberg said Facebook, for the first time, would now make it possible for anyone to see any political ads that run on Facebook, no matter whom they target.

Facebook also will demand that political advertisers disclose who is paying for the advertisements, a requirement that under U.S. law applies to political ads on television but not on social media.

Zuckerberg said on Thursday the changes would help address concerns that governments including Russia are using Facebook ads to meddle in other countries' elections.

U.S. intelligence agencies concluded that Russia engaged in cyber attacks to sway the 2016 election against Democrat Hillary Clinton in favor of Trump. U.S. congressional investigators and a special counsel are investigating the matter. Moscow has denied any interference.

While Trump dismissed the advertisement controversy, his secretary of state, Rex Tillerson, expressed concern.

"Well, I think all of these social media providers are faced with many challenges," Tillerson said on ABC's "Good Morning America," pointing to their use by militant groups around the world as well as in election campaigns.

"But they also have responsibilities," he said. "And I think they're going to have to think carefully about their responsibilities in this regard."

U.S. election law bars foreign nationals and foreign entities from spending money to expressly advocate the election or defeat of a candidate.