Facebook has closed a big political advert loophole ahead of November's U.S. presidential election.
Since 2018, the social media giant has attached a "paid for by" disclaimer to political ads.
It followed a backlash for failing to stop Russia from using its platforms to influence the 2016 U.S. election.
But the label disappeared once people shared the ads to their own feeds.
Critics said the loss of the label undermined its usefulness and allowed misinformation to continue spreading unchecked.
The company says it now considers it important to disclose if a post was at one point an advert.
Facebook introduced a similar labelling approach for state news media earlier this month.
But that label also sometimes drops off with sharing - and doesn't appear when users post their own links to those outlets.
Facebook is facing demands to do more to combat false viral information before the U.S. election on November 3.
In a USA Today op-ed on Tuesday (June 16), its founder Mark Zuckerberg pledged to display a Voting Information Center at the top of news feeds for users in the United States.