Facebook told the US Congress in June that Mail.Ru was among other companies that were given extra time past initial May 2015 deadline to ensure their compliance with Facebook tighter policy on data collection by third-party apps. Mail.Ru was given two weeks to stop its messaging apps from allowing users to see Facebook friends lists.
"In the last 6 months, we've learned that Facebook had few controls in place to control the collection and use of user data by third parties. Now we learn that the largest technology company in Russia, whose executives boast close ties to [Russian President] Vladimir Putin, had potentially hundreds of apps integrated with Facebook, collecting user data. If this is accurate, we need to determine what user information was shared with mail.ru and what may have been done with the captured data," Warner told the CNN broadcaster on Tuesday.
Facebook has found no signs of data misuse by Mail.Ru, the social network's head of product partnerships, Ime Archibong, told the broadcaster.
"Mail.ru, one of the top five largest internet companies in the world, has built apps for the Facebook platform and for other major platforms, including iOS and Android for years. We've found no indication of misuse with Mail.ru. If we find misuse, we ban the developers," Archibong was quoted as saying.
Facebook told the broadcaster that it had reached out to Mail.Ru as part of the general investigation into data use it was conducting. The Russian company told the CNN it had not been contacted by the social media giant about the inquiry.
Yury Milner, investor and Mail.Ru founder, pointed out in an open letter that DST Global had never sought control over Facebook or Twitter and sold its shares several years before the Panama Papers leaks remarked on the connection. Facebook confirmed DST Global had been a passive investor.
Milner sold his stake in Mail.Ru as well, soon after the company went public in 2010.
Facebook became enmeshed in a scandal of third-party applications using its data after media reported in March that Cambridge Analytica political consultancy firm had harvested information of millions of Facebook users through such an application. The company, which has filed for bankruptcy since the scandal broke out, is suspected of using the information to better target its ads campaigns.
Several probes into Facebook and Cambridge Analytica are ongoing in the United States and the United Kingdom. In April, media reported that US Congress panels were looking into whether Russia had any access to Facebook users data and if any companies linked to the 2016 presidential campaign of Donald Trump might have provided Moscow with such data.
Russian officials have strongly refuted repeated US allegations of Moscow's interference in US 2016 presidential campaign, pointing out that no proof of any such meddling had ever been shown and the US side appeared to use this issue to divert attention from other topics.