Instagram said on Monday it will start removing “inauthentic” likes, followers and comments from accounts that use third-party apps as a way to inflate their popularity.

People who use these apps will receive a warning letting them know their artificial activity on Instagram has been removed, the company said in a blog post. Instagram will also ask these users to change their passwords, which had been shared with these third-party apps, as a way to secure their accounts.

“We’ve built machine learning tools to help identify accounts that use these services and remove the inauthentic activity. This type of behavior is bad for the community, and third-party apps that generate inauthentic likes, follows and comments violate our community guidelines and terms of service,” Instagram said in the blog post.

Instagram did not name the third-party apps that it believes are a signal of inauthentic activity. However, a quick online search brings up lists of dozens of apps promising to help people inflate their following.

Anyone who has a public Instagram account has probably had the experience of an account they’ve never heard of liking a few of their photos or posting a vague comment, such as “Nice one!” as a way to attract new followers.

Instagram did not immediately respond a a request for comment. The blog post also did not quantify how much of the activity on Instagram could be classified as “inauthentic” or offer any other details as its efforts to remove fake accounts.

The action comes at a time when engagement on Instagram is shifting to its stories feature. But it also comes at a time when Facebook is under pressure to clean up inauthentic activity, secure its platforms and create more meaningful engagements.

Earlier this month, Facebook announced it had removed 85 Instagram accounts that were believed to be “engaged in coordinated inauthentic behavior.” However, Instagram has been scrutinized for not doing enough to remove hate posts from its site, while instead focusing on other targets, such as censoring photos of nudity.

The photo sharing app was purchased by Facebook for $1 billion in 2012. It now has more than 1 billion monthly active users.

Instagram co-founders Kevin Systrom and Mike Krieger left the company in September after tension had reportedly been mounting with Facebook CEO Mark Zuckerberg over changes to the product.