The Susan B. Anthony List, one of the biggest anti-abortion rights groups in the U.S., said Friday that Facebook blocked its political advertisements for including information about abortion later in pregnancy, citing a third-party that marked the ads’ claims as “partly false.” That fact-checker, conservative blog The Dispatch, has since posted an apology and retracted its fact check. 

The anti-abortion rights group’s accusation comes as social media giants have moved to clamp down on misinformation ahead of the November election.

In the 15-second ad, the SBA List claims that former Vice President Joe Biden and running mate Kamala Harris hold “extreme” views on abortion, and that they “support abortion up until the moment of birth,” an emotional accusation that doctors say isn’t reflective of medical reality. It’s also a practice that neither candidate has specifically addressed.

According to a screenshot tweeted by the SBA List, Facebook told the anti-abortion rights groups that the “ad can’t run” given that “ads must not include claims debunked by third-party fact checkers.” 

The ad is still viewable on the Facebook page for “Women Speak Out PAC,” a partner of the SBA List. But beneath the ad, Facebook includes a disclaimer that says, “Partly False Information” and directs readers to a fact check published by the Dispatch. It was not clear why the ad was able to run on Women Speak Out PAC’s page, given the SBA List’s claim that it was banned on theirs. 

In the now deleted post, the fact-check said the claim was inaccurate because Biden has not addressed abortion later in pregnancy and neither candidate has referenced abortion “up until birth,” which the ad claims they support. But the Dispatch said on Friday afternoon that the fact-check was “published in error.”

“The fact-check was published in error and in draft form, before it had been through final edits and our own internal fact-checking process,” the group said. “As a result, the viral post was assigned a ‘partly false’ rating that we have determined is not justified after completing The Dispatch fact-checking process.”  

The SBA List criticized Facebook in an email to CBS News on Friday. “Big Tech and the media are teaming up to run interference for the Biden-Harris campaign on what is a losing issue for Democrats – their shameful support for abortion on demand through birth,” said Marjorie Dannenfelser, the president of the SBA List. “This is the latest example of Facebook censoring political speech and is perfectly timed to shut down SBA List’s vital digital communications.”

Facebook did not immediately respond to emails requesting comment.

With November’s election just weeks away, social media giants like Facebook and Twitter have intensified policies to stop the spread of false information. In September, Facebook rolled out a series of sweeping changes to limit voter misinformation and within hours applied those news rules to a post from President Trump. Last week, Twitter rolled out their own temporary changes in an effort to stem the flow of misinformation surrounding the election.

Anti-abortion rights activists, and the president himself, have repeated similar misleading claims about abortion later in pregnancy, claiming that Democrats are in favor of abortion “up until the moment of birth.”

The concept of “abortion up until birth” is not something that happens in medical practice, said Jen Villavicencio, a practicing OB/GYN, in an interview with CBS News last week. Terminations after about 24 weeks of pregnancy are generally only legally allowed to happen in cases of severe fetal abnormalities, such as when the fetus is no longer viable, or to save the life of the patient. Abortions later in pregnancy are extremely rare and only allowed in very limited circumstances.

Biden and Harris have both said they support current abortion laws, which allow for abortion later in pregnancy in those limited circumstances. Only seven states allow for abortion at any point in a patient’s pregnancy, according to data compiled by the Guttmacher Institute, a reproductive research group that supports abortion access.

Abortions later in pregnancy are also exceedingly rare, according to the CDC. In 2016, the most recent year for which data is available, more than 90% of all abortions occured in the first 13 weeks of a patient’s pregnancy. Only 1.3% of abortions in 2016 happened at or after 21 weeks of pregnancy, according to the CDC.