WhatsApp has been recently warned by European privacy watchdogs about the changes made to WhatsApp's privacy that results to user data sharing with Facebook, according to BBC news.

The data watchdogs have told WhatsApp and Facebook that the deal must be halted until the legality of the same has been thoroughly checked, as reported by Independent.co.uk.

Apparently, if the deal will be proven illegal, then it will be required to stop.

The serious concerns by the watchdogs started when WhatsApp announced during the past weeks that it would begin passing on information about the people who use it to Facebook, so that its parent company, could utilize the data in targeting better advertisements, as explained by Independent.co.uk.

However, many criticized its decision because WhatsApp previously pledges that it will remain independent of Facebook. It was also reported that Facebook bought the messaging app in early 2014 for $19bn (£16bn), as per BBC.

BBC reported that the decision to share user data impelled investigations by the data protection bodies across Europe.

According to Independent.co.uk, the collective association of data watchdogs known as Article 29 Working Party, requested that WhatsApp "communicate all relevant information to the Working Party as soon as possible and urged the company to pause the sharing of users' data until the appropriate legal protections could be assured".

The watchdog also specifically noted the purported "great uncertainty" caused in the minds of WhatsApp users.

The Working Party advised that more work should be done to guarantee that regional rules governing privacy were not breached when information were passed from one company to another, as further reported by BBC.

WhatsApp is one of the leading messaging and calling apps with more than one billion people in over 180 countries users. They already conveyed that they are coordinating with the data watchdogs to discuss their concerns.

Meanwhile, a WhatsApp spokeswoman already said that, "We've had constructive conversations, including before our update, and we remain committed to respecting applicable law," in her statement in BBC news.