US lawmakers slam social media giant

Facebook drew fresh criticism from US lawmakers following revelations that it allowed Chinese smartphone makers, including one deemed a national security threat, access to user data.

The world's largest social network confirmed late Tuesday that China-based Huawei -- which has been banned by the US military and a lightning rod for cyberespionage concerns -- was among device makers authorized to see user data.

Facebook, which has been blocked in China since 2009, also had data-access deals with Chinese companies Lenovo, OPPO and TCL, according to the company, which had similar arrangements with dozens of other devices makers.

US lawmakers expressed outrage over the matter at a time when officials were trying to block their access to the US market over national security concerns. 

"Mark Zuckerberg needs to return to Congress and testify why @facebook shared Americans' private information with questionable Chinese companies," Massachusetts Democrat Senator Ed Markey said on Twitter.

"This could be a very big problem," tweeted Senator Marco Rubio, a Florida Republican.