WASHINGTON – More than 17,000 Facebook members have joined a class action lawsuit accusing the social network of violating data protection law and supporting spying by America’s National Security Agency.

The suit was launched on 1 August by a 26-year-old Austrian law student, Max Schrems, who filed his claim to be heard in his home country. He called for 1 billion Facebook users to join his case.

By Monday, 5,000 Facebook members had signed up for the action via a specially created app that can be accessed from desktop computers and mobile devices, handing over details of their Facebook memberships, their addresses and scans of identity documents. By Tuesday, more than three times that number were on board.

Schrems, who described the response to his appeal as “giant”, told the Reuters: “The emails and feedback have been really positive and what is interesting is that many people say finally someone is doing something in this direction.”

The case is being brought against Facebook Ireland, which is based in Dublin and runs the network’s activities outside of America.

The world’s biggest social network has 1.32 billion users, and its shares are trading at a record high, valuing the company at almost $200bn.

But Schrems claims Facebook Ireland has committed unlawful acts, including “support of the NSA’s ‘PRISM’ surveillance programme”, tracking Facebook users on external websites, for example through “like” buttons, passing user data to external applications without authorisation, and not securing effective consent for many types of data use.