Facebook on Monday pulled and then later restored ads by Democratic presidential hopeful Senator Elizabeth Warren calling for tech giants to be broken up.
"We removed the ads because they violated our policies against use of our corporate logo," Facebook told AFP.
"In the interest of allowing robust debate, we are restoring the ads," it said, putting the number of affected ads at four.
Other ads calling for the breakup of Facebook and other US tech giants ran as intended, according to the California-based social network.
"Curious why I think FB has too much power?" Warren said in a message fired off on Twitter.
"Let's start with their ability to shut down a debate over whether FB has too much power."
Warren went on to thank Facebook for restoring her ads and called for a "social media marketplace that isn't dominated by a single censor."
She unveiled a proposal just days earlier to break up Big Tech, arguing that firms such as Amazon, Google and Facebook hold " too much power" in society.
Warren said that as president, she would press for legislation to designate big online companies with revenues of at least $25 billion as "platform utilities" barred from owning "any participants on that platform."
The Massachusetts senator said she would also appoint antitrust enforcers "committed to reversing illegal and anti-competitive tech mergers," including acquisitions in recent years by Amazon, Facebook, and Google.
"Today's big tech companies have too much power - too much power over our economy, our society and our democracy," she wrote in a blog post on Medium.
"They've bulldozed competition, used our private information for profit, and tilted the playing field against everyone else."
The proposal comes amid a growing "techlash" movement in the United States against the firms, which have grown to become the world's most valuable, and a series of antitrust investigations in Europe.
Critics accuse the firms of mishandling private user data and of abusing their dominance of certain sectors such as online retail and Internet search.