The United Kingdom parliament revealed two letters on Tuesday written by Facebook (FB) and Twitter (TWTR) representatives indicating that they will share unspecified information related to campaign activity conducted on their social media platforms.

Similar to the United States 2016 presidential election, U.K. lawmakers believe that Russia may have influenced the 2016 Brexit vote in which the U.K. voted to leave the European Union. UK lawmakers allege that Russia may have spread so-called fake news and propaganda to mislead the public, thus manipulating the vote.

Facebook U.K. policy director Simon Miller wrote that Facebook is “considering how we can best respond to the Electoral Commission’s request for information and expect to be able to respond to them by the second week of December.”

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“In the meantime, we remain committed to assisting your Committee’s wider inquiries into ‘fake news’ and hope that you found our written evidence to the Committee helpful,” Milner wrote.

Nick Pickles, Twitter’s head of public policy for the U.K., said that the company is “currently undertaking investigations into these questions and intend to share our findings in the coming weeks.”

In early November, U.S. lawmakers grilled Facebook, Twitter, and Google over the companies’ roles in distributing misinformation to users. As part of the congressional testimony, Facebook revealed that a Russian organization spread divisive messages through the social network that reached about 126 million Facebook users based in the U.S. in prelude to the 2016 presidential election.