Facebook says it will ban a "wider category of hateful conduct" in ads as the embattled social media giant moved to respond to widening protests over its handling of inflammatory posts.
Chief executive Mark Zuckerberg said Facebook will add tags to posts that are "newsworthy" but violate platform rules - following the lead of Twitter, which has used such labels on tweets from US President Donald Trump.
The move comes as Unilever joined a growing list of firms on Friday to boycott Facebook as part of a protest by activists seeking tougher action by Facebook on content promoting discrimination and violence.
The new policy on hateful content in ads will "prohibit claims that people from a specific race, ethnicity, national origin, religious affiliation, caste, sexual orientation, gender identity or immigration status are a threat to the physical safety, health or survival of others," Mr Zuckerberg said on his Facebook page.
"We're also expanding our policies to better protect immigrants, migrants, refugees and asylum seekers from ads suggesting these groups are inferior or expressing contempt, dismissal or disgust directed at them."
Earlier on Friday Unilever had said it would stop advertising on Facebook, Instagram and Twitter in the United States for the rest of the year.
The consumer goods company, which owns brands including Dove Soap and Lipton tea, joins a growing advertising boycott against Facebook as part of the Stop Hate for Profit campaign started by US civil rights groups after the death of George Floyd.
The effort is calling on Facebook, which owns Instagram, to do more to stop hate speech and misinformation.
Shares of Facebook and Twitter both fell more than seven per cent.
"Continuing to advertise on these platforms at this time would not add value to people and society. We will be monitoring ongoing and will revisit our current position if necessary," Unilever said in a statement.
The Stop Hate for Profit campaign asks businesses not to advertise on Facebook's services in July.
It focuses on specific recommendations for Facebook, though Twitter has also long been under pressure to clean up alleged abuses and misinformation on its platform.
"We have developed policies and platform capabilities designed to protect and serve the public conversation, and as always, are committed to amplifying voices from under-represented communities and marginalized groups," said Sarah Personette, vice president for Twitter's Global Client Solutions.
"We are respectful of our partners' decisions and will continue to work and communicate closely with them during this time."
More than 90 advertisers including Verizon Communications and The North Face, a unit of VF Corp, have joined the campaign, according to a list by ad activism group Sleeping Giants, a partner in the campaign.
Earlier this week, ice-cream maker Ben & Jerry's, a unit of Unilever, said it would pull its Facebook and Instagram ads in the United States.
In an earlier statement, a Facebook spokeswoman had pointed to its civil rights audit and investments in Artificial Intelligence that allow it to find and take action on hate speech.
"We know we have more work to do, and we'll continue to work with civil rights groups, GARM, and other experts to develop even more tools, technology and policies to continue this fight," she said, referring to the Global Alliance for Responsible Media.
