Google has confirmed that automatic spam protection within the default Android Messages app has begun rolling out to some users. The rollout was first spotted by Android Police. After displaying a notification to let the user know that the feature has been enabled, the app will begin analyzing messages that are sent to you in order to detect and proactively block spam messages. However, privacy concerns have been raised about the way the feature stores the associated phone numbers.

Automatic spam protection, which is opt-out by default, can be turned off from within the advanced settings menu. Google was unable to provide an exact timescale for the rollout of the new feature, but it said that it’s currently being released gradually in a few countries, and the company plans to release it more widely “in the coming months.”

“Google temporarily stores the phone numbers of people sending and receiving messages with you.”

Google was quick to downplay privacy concerns about the way the feature tracks and stores details about the messages sent. Messages users can already report spam texts, but by working automatically in the background, Google now collects and temporarily stores phone numbers. In a statement provided to The Verge, a spokesperson from Google said:

To help identify spammers, Google temporarily stores the phone numbers of people sending and receiving messages with you and the times they messaged with you, but does not store your phone number or the content of these messages.

However, Google’s support site, which was recently updated with details about data protections, notes that if you choose to manually report a message as spam, then the full contents of the message is sent. Google’s software may prompt you to submit a manual report if it identifies a message as spam, at which point “up to 10” of the suspected spammer’s messages will be sent to Google. Meanwhile, carriers who support spam reporting may receive a separate copy of the spammer’s last message and phone number.

So what about texts sent between Messages users who have spam protection enabled? In that case, Google would theoretically store both of their numbers. However, in this case, Google confirmed to The Verge that data wouldn’t be associated directly between the accounts, even if one user is reported for spamming.

The new feature comes just weeks after the Federal Communications Commission voted to reclassify text messages as information services in an attempt to fight phone spam. The regulator argued that this was necessary in order to give network carriers more power to block unwanted messages. At least one consumer advocacy group criticized the change and said that it could allow phone companies to discriminate against messages and harm both consumers and free speech.