Washington DC CNN  — 

Facebook has stopped the Trump campaign from running its racist anti-immigration commercial as an ad on the site.

“This ad violates Facebook’s advertising policy against sensational content so we are rejecting it. While the video is allowed to be posted on Facebook, it cannot receive paid distribution,” Facebook said in a statement Monday afternoon.

The move came shortly after NBC and Fox News said they would stop airing the ad across their networks. CNN had previously determined that the ad is racist and declined to sell airtime for it.

The Trump campaign began running the ad on Facebook on Sunday, targeting voters in Florida and Arizona. By Monday morning, it had reached millions of users on the platform.

A Facebook spokesperson said the ad had been allowed to run in error.

According to data from Facebook’s ad archive, Donald J. Trump for President, Inc. spent at least $20,000 and possibly as much as $80,000 on the ad buy.

The ad tries to motivate GOP turnout by playing on fears of the migrants traveling through Mexico.

“We have Community Standards that outline what is and isn’t allowed on Facebook. However, when it comes to ads on Facebook, we have a higher set of standards for what can run in an ad. Our Advertising Policies are more restrictive because they take paid distribution. Under our Community Standards, this video is allowed to be posted on Facebook,” the spokesperson said.

Facebook’s ad problem

Facebook’s reversal on the spot is another misstep from a company that pledged to improve its handling of political ads.

In 2016, a Russian group ran ads targeting American voters in the lead up to the presidential election. The company has since introduced disclaimers on political ads that are supposed to show who paid for them.

But last week, Vice News, posing as a political ad-buyer, got approval from Facebook to run ads in the name of every single one of the US’ 100 senators. Vice News did not end up buying the ads. This came after Vice News had previously received approval from Facebook to run ads “Paid for” by Islamic State and Vice President Mike Pence.

Separately, CNN Business found one advertiser breaking Facebook’s rules twice in one week. Facebook missed both violations and only acted in both instances after CNN inquired about it.

– CNN Business’ Oliver Darcy and Brian Stelter contributed to this story.