Facebook says it will back a new US cyber-security bill that will enable the government to access web users' private data on suspicion of a cyber threat.
The act, dubbed the Cyber Intelligence Sharing and Protection Act (Cispa) is aimed at enabling easier information-sharing between security agencies and private internet firms.
Facebook, AT&T, Intel, Verizon, and Microsoft are among some 800 US-based firms that have reacted positively to the bill, which is due before Congress on 23 April.
In a blog post, Facebook's vice-president of US public policy, Joel Kaplan, said Facebook would continue to safeguard personal information of its 845 million-plus users.
But internet privacy groups claim that Cispa is aimed at file sharers rather than hackers, according to the BBC. Proposals for similar snooping legislation in the UK have also been strongly criticised by civil liberties groups, forcing government to reconsider.
The Electronic Frontier Foundation, the American Civil Liberties Union, the Sunlight Foundation and Avaaz.org have all expressed concerns about the extent to which the US government would be able to monitor private information.
The Sunlight Foundation's John Wonderlich wrote in a blog post that Cispa "is terrible on transparency" and that the shared personal data between firms and the government would be exempt from the Freedom of Information Act (FOIA).
"The FOIA is, in many ways, the fundamental safeguard for public oversight of government's activities. Cispa dismisses it entirely, for the core activities of the newly proposed powers under the bill," he wrote.
The Electronic Frontier Foundation (EFF) said in a statement on its website that the language used in the act was too vague.
"The broad language around what constitutes a cyber-security threat leaves the door wide open for abuse," the EFF said.