Facebook will soon tell its users whether they fell for Russian fake news: The social network announced Wednesday that it is working on a tool that will let its users check whether they liked or followed one of the Facebook or Instagram accounts linked to Russia’s Internet Research Agency, which spread misinformation on both services between January of 2015 and August of 2017.

“It is important that people understand how foreign actors tried to sow division and mistrust using Facebook before and after the 2016 US election,” the company said in a news release. “That’s why as we have discovered information, we have continually come forward to share it publicly and have provided it to congressional investigators. And it’s also why we’re building the tool we are announcing today.”

The tool will be made available by the end of the year as part of Facebook’s help center.

Facebook previously revealed that the Internet Research Agency ran a number of fake accounts advocating for a wide variety of causes on both sides of the political spectrum. Some of these Facebook pages supported the candidacy of Donald Trump and mobilized against immigration, while others imitated the Black Lives Matter movement.

In fact, in some instances, the Internet Research Agency even mobilized demonstrators for and against certain causes to take to the streets at the same time in an apparent attempt to sow chaos.

Facebook previously revealed that accounts controlled by the Internet Research Agency published some 80,000 posts between early 2015 and mid-2017. The company also disclosed some 4000 ad buys by the group, and said that its post may have been seen by as many as 140 million people.

However, not all of those people will be able to use the tool announced by Facebook Wednesday. The tool will only show users if they liked one of the pages that spread the propaganda, not whether they read one of those 80,000 posts.