https://www.theverge.com/2017/9/21/16346792/facebook-congress-russian-ads-reversal

In a major reversal, Facebook agreed today to share with Congress more than 3,000 ads linked to a Kremlin-linked group believed to attempted to influence the US political election. The company had previously shared the ads with Robert Mueller, the special counsel currently investigating Russian interference in the presidential election. Facebook had resisted sharing the information more broadly, saying it would threaten advertisers’ privacy.

“Disclosing content is not something we do lightly under any circumstances,” Colin Stretch, the company’s general counsel, said in a blog post. “We are deeply committed to safeguarding user content, regardless of the user’s nationality, and ads are user content. Federal law also places strict limitations on the disclosure of account information. As our biannual transparency reports make clear, we carefully scrutinize all government data requests, from here and abroad, and we push back where they do not adhere to those legal limitations.”