Two privacy groups filed a formal complaint with the FTC over Facebook’s proposed $19 billion acquisition of WhatsApp.

The complaint claims that “WhatsApp built a user base based on its commitment not to collect user data for advertising revenue. Acting in reliance on WhatsApp representations, Internet users provided detailed personal information to the company including private text to close friends. Facebook routinely makes use of user information for advertising purposes and has made clear that it intends to incorporate the data of Whats App users into the user profiling business model. The proposed acquisition will therefore violate WhatsApp users’ understanding of their exposure to online advertising and constitutes an unfair and deceptive trade practice, subject to investigation by the Federal Trade Commission.”

This complaint adds up to concerns brought by European privacy regulators according to which the acquisition could unleash privacy investigations all over the EU. Jacob Kohnstamm, who leads a group of EU privacy officials known as the “Article 29 Data Protection Working Group” said last month that the acquisition “may spur interest from authorities who so far ignored the emergence of WhatsApp”.