A software tool to be released by the end of this year will allow users to see whether they engaged with Facebook pages or Instagram accounts considered part of a Russian effort to meddle with last year's US election.
Facebook said on Wednesday it would build a web page to allow users to see which Russian propaganda accounts they have liked or followed.
The announcement came after US lawmakers demanded that the social network be more open about the reach of the accounts. And they called the announcement a positive step.
The web page, though, would fall short of their demands that Facebook individually notify users about Russian propaganda posts or ads they were exposed to.
Facebook, Google and Twitter are facing a backlash after saying Russians used their services to anonymously spread divisive messages among Americans in the run-up to the 2016 US elections.
US lawmakers have criticised the tech firms for not doing more to detect the alleged election meddling, which the Russian government denies involvement in.
Facebook says the propaganda came from the Internet Research Agency, a Russian organization that according to lawmakers and researchers employs hundreds of people to push pro-Kremlin content under phony social media accounts.
As many as 126 million people could have been served posts on Facebook and 20 million on Instagram, the company says. Facebook has since deactivated the accounts.
Facebook, in a statement, said it would let people see which pages or accounts they liked or followed between January 2015 and August 2017 that were affiliated with the Internet Research Agency.
The tool will be available by the end of the year as "part of our ongoing effort to protect our platforms and the people who use them from bad actors who try to undermine our democracy," Facebook said.
The web page will show only a list of accounts, not the posts or ads affiliated with them, according to a mock-up. US lawmakers have separately published some posts.
It was not clear if Facebook would eventually do more, such as sending individualized notifications to users.
Lawmakers at congressional hearings this month suggested that Facebook might have an obligation to notify people who accessed deceptive foreign government material.
Senator Richard Blumenthal, a Democrat who had asked for notifications, said Facebook's plan "seems to be a serious response" to his request.
"My hope is that it will be a responsible first step towards protecting against future assaults on its platform," he said in a statement.
Representative Adam Schiff, a Democrat, called it a "very positive step" and said lawmakers look forward to additional steps by tech companies to improve transparency.