The ads were shown on the Facebook pages of Trump and Vice President Mike Pence, which have a combined 27.5 million followers on the popular social network. Trump's reelection campaign has spent aggressively to advertise on Facebook, including a combined $35.6 million on Trump and Pence's pages since May 2018.

U.S. households are slated to receive information about how to complete the actual census starting next week.

“There are policies in place to prevent confusion around the official U.S. Census and this is an example of those being enforced," Facebook said in a statement.

Facebook created those policies last year after civil society advocates expressed fears about how misinformation on social media would be used to suppress participation in the census, particularly among Americans who identify as racial or ethnic minorities. The rules prohibit any misrepresentation of who is eligible to participate in the census and how to do so.

The ads were brought to light by Popular Information, a newsletter created by journalist Judd Legum, who founded the website ThinkProgress and worked on Hillary Clinton's 2008 presidential campaign. Facebook initially told the publication that the ads did not violate its policies before reversing course, Legum wrote.

Earlier in the day, House Speaker Nancy Pelosi chastised Facebook's initial decision.

"We told them to take down that site," Pelosi said. "It's a lie and it undermines who are are. It may be good for their profits, but that's what's counts for them. It's not what counts for us and the Census."