The FBI is examining an alleged plot where antifascist activists "planned to disrupt U.S. law enforcement and military security operations at the US/Mexican border."

The activists are accused of seeking to purchase guns from a "Mexico-based cartel associate known as Cobra Commander," according to a December FBI document obtained by the San Diego Union-Tribune. The FBI cautioned multiple agencies that the activists were aiming to “stage an armed rebellion at the border.”

The FBI report was issued to agencies including the Department of Homeland Security, U.S. Customs and Border Protection, the Central Intelligence Agency, and the National Security Administration, and others.

But so-called Cobra Commander Ivan Riebeling and Evan Duke — both individuals named in the FBI — denied the accusations and said the plot didn’t make sense.

“It doesn’t make any sense that someone in the United States would purchase guns in Mexico,” Riebeling told the San Diego Union-Tribune. “And the Hondurans certainly didn’t bring money to buy guns. It doesn’t make any sense; in fact it’s extremely absurd to say the Hondurans wanted to attack the United States at the border.”

Two law enforcement officials said that the investigation is still being conducted. The document was provided to the Union-Tribune by an anonymous source who did not want to be named and did not consent to providing the document online since the investigation is ongoing.

Such activists that label themselves “antifa” or “antifascist” are tied to often-violent left-wing protest groups. For example, an alleged antifa leader was arrested and charged earlier this year with aggravated assault and ethnic intimidation in connection to an attack on two U.S. Marines.