The company said it had observed persons belonging to the American Guard group discussing such an action.
The company said it had planned to take action against both groups, but had accelerated the process when they saw how the groups discussed the protests.
Employees working as part of the company's team to combat dangerous and inauthentic organizations operating on the platform spoke to CNN on Tuesday.
Employees said that the company would take action against people using the platform to organize violence regardless of their political affiliation.
The fake account, @ANTIFA_US, tweeted Sunday, "ALERT Tonight & # 39; s the night, Comrades Tonight we say" F ** k The City "and we move into the residential areas … the white caps … and we take what is our #BlacklivesMaters #F ** kAmerica. "
The account caught the attention of President Donald Trump's son Donald Trump jr.
"Absolutely insane," Trump Jr. wrote. on Instagram and shared a screenshot of the tweet, "Just remember what ANTIFA really is. A terrorist organization! They don't even pretend anymore."
A spokesman for Donald Trump jr. Did not comment on CNN Tuesday morning, but later the post was removed from Trump Jr. s Instagram feed. There is no indication that Trump Jr. knew who was behind the account or that it was false.
Facebook said Tuesday night that it had found some affiliate accounts on its platforms after Twitter shared information about the fake account – the accounts have been removed from Facebook, staff said. The accounts had not been used recently, staff added.