Three men accused of being members of white supremacist group The Base pleaded not guilty Tuesday to charges related to an alleged plan to foment violence at a Virginia gun rights rally. Former Canadian Armed Forces reservist Patrik Mathews and Mark Lemley Jr. made their pleas in a Maryland court on firearms charges and others. Both Mathews, 27, and Lemley, 33, allegedly discussed the “the planning of violence” at the Richmond, Virginia rally—with Mathews claiming such an incident could lead to a “full blown civil war.” William Garfield Bilbrough IV, 19, also pleaded not guilty to charges including conspiracy to “transport and harbor certain aliens.” Prosecutors say Bilbrough participated in early discussions about the rally, but then tried to distance himself from the group.

The three men were arrested by the FBI as part of a larger probe into The Base, with Georgia and Wisconsin officials arresting others with links to the group. Mathews and Lemley are also facing charges in Delaware.