"Unfortunately, this is yet another instance of actions by US technology companies potentially impacting American national security," wrote Markey, "and it is incumbent upon our committee to exercise oversight in this regard." Markey is the ranking member of the East Asia, the Pacific and International Cybersecurity Policy Subcommittee and he sent a letter, cosigned by Senator Richard Blumenthal (D-CT), to Zuckerberg earlier this week, seeking answers to questions over the recently reported practice.

Mark Zuckerberg needs to return to Congress and testify why @facebook shared Americans' private information with questionable Chinese companies. Our privacy and national security cannot be the cost of doing business. https://t.co/nyRbc8xwBY — Ed Markey (@SenMarkey) June 6, 2018

This weekend, the New York Times reported that Facebook had provided detailed user data to at least 60 mobile device makers, which allowed them to offer Facebook-like features at a time when a Facebook app wasn't available for all devices. While these partnerships allowed companies to offer Facebook's messaging, Like buttons and address books to their customers, it also reportedly gave them information on Facebook users like political leanings, religious affiliations, events they planned to attend and relationship statuses. The setup also let these companies retrieve information from their customers' Facebook friends -- and their friends' friends -- without those individuals' consent.

Facebook has said it has no evidence that any of the companies abused the partnerships and claims it had strict control over the data use. But with concerns over the recent Cambridge Analytica scandal still brewing, many are worried that this is yet another example of Facebook infringing on its users' privacy. Along with those fears, Markey is also concerned about the implications of sharing this type of data with companies that US officials have deemed to be a security risk. Earlier this year, officials with the FBI, CIA and NSA warned US residents about using devices manufactured by Huawei. "We're deeply concerned about the risks of allowing any company or entity that is beholden to foreign governments ... to gain positions of power inside our telecommunications networks," FBI Director Chris Wray told the Senate Intelligence Committee. Congress has also sought to ban government agencies from working with Huawei.

"Although Facebook officials stated that 'all the information from these integrations with Huawei was stored on the device, not on Huawei's servers,' I have serious concerns about the foreign policy implications of American companies providing such information to Chinese companies," wrote Markey.