The FBI is investigating anti-fascist activists for an alleged plot to buy guns from a Mexican cartel in order to “stage an armed rebellion” at the southern border, according to an unclassified document obtained by The Chicago Tribune.The FBI document, from December of 2018, warns of militant antifa activists planning to “disrupt security operations” at the U.S.-Mexico border. The group allegedly planned to buy guns from a Mexican cartel associate known as Cobra Commander, in order to “stage an armed rebellion at the border.”The source who provided it to the San Diego Tribune asked the outlet not to publish the six-page document because the investigation is ongoing, and the outlet cited two additional law enforcement officials who confirmed the news. The FBI has warned dozens of law enforcement agencies in both Mexico and the United States of the alleged plot.Two of the men named in the report told the San Diego Tribune the allegations are absurd.