The US Federal Trade Commission (FTC) will “carefully review” changes made to WhatsApp’s privacy policy through which it will share user data with parent Facebook, following complaints from two privacy groups.

In a letter to the Center for Digital Democracy and the Electronic Privacy Information Center, the FTC acknowledged complaints regarding the “data collection, use, combination and sharing practices of WhatsApp user data such as mobile phone number and other account information with Facebook”.

However, it added that any probe would not be made public until it decided to issue a formal complaint or to close the investigation, due to which it can “neither confirm nor deny” that it is conducting a investigation.

Last month, WhatsApp explained its move, saying that by coordinating more with Facebook, it will be able to do track basic metrics about how often people use its services and better fight spam.

Also, by connecting phone numbers with Facebook’s systems, it believed Facebook can offer better friend suggestions and show users more relevant ads.

This was met by criticism from many. For instance, Europe’s privacy regulators are also looking into the matter “with great vigilance”.