WASHINGTON: Mobile messaging service WhatsApp on Thursday announced it would begin sharing subscriber data with parent Facebook, giving advertisers better access to information on WhatsApp's one billion-strong user base.

The company said the change would allow Facebook to target advertising at WhatsApp users who are also on the social media platform, and help WhatsApp fight spam on its service.

But the move was sure to raise eyebrows among privacy advocates.

“By connecting your phone number with Facebook's systems, Facebook can offer better friend suggestions and show you more relevant ads if you have an account with them,” WhatsApp said in a statement.

“For example, you might see an ad from a company you already work with, rather than one from someone you've never heard of.”

Microsoft's popular calling and messaging platform Skype, a WhatsApp competitor, already serves up advertising to users.

WhatsApp said the change would not involve third-party banner adds or other undesirable content.

The decision comes four months after WhatsApp rolled out strong end-to-end encryption as a default feature for all users, saying this made the content of their communications impenetrable to all but those sending or receiving a given message.

“Even as we coordinate more with Facebook in the months ahead, your encrypted messages stay private and no one else can read them. Not WhatsApp, not Facebook, nor anyone else,” the company said.

Facebook acquired WhatsApp in February 2014 for $16 billion.