The FBI arrested three members of a neo-Nazi group called “The Base” on Thursday morning, days ahead of a pro-gun rally in Richmond that is attracting fringe figures and has already prompted a state of emergency declaration.

The three suspects—Brian Mark Lemley, William Garfield Bilbrough, and Canadian fugitive Patrik Mathews—face a variety of gun charges. Lemley and Bilbrough are also accused of illegally harboring Mathews, a former Canadian military reservist who fled his home country after being accused of being a recruiter for The Base. The trio is expected to face a federal judge in Maryland on Thursday afternoon.

The suspects had discussed traveling to Richmond, Virginia, for a Jan. 20 rally in front of the state Capitol to protest new gun control legislation, The New York Times reported. The rally has become a flashpoint for the fringe right, prompting Gov. Ralph Northam to declare a four-day state of emergency and ban guns from the Capitol complex.

Lemley and Mathews had allegedly built an assault rifle and amassed hundreds of rounds of ammunition before their arrest, according to the FBI. On a recording, Lemley said he had made the gun into an illegal machine gun and made plans to hide it from federal agents, according to the FBI.

“Oh oops, it looks like I accidentally made a machine gun,” Lemley, a former cavalry scout in the U.S. Army, said, according to the affidavit.

“I’m going to stow it here until next week, just in case the ATF [Bureau of Alcohol, Tobacco and Firearms] shows up tomorrow,” he told Mathews.

“Um, if they show up here, we got other problems,” Mathews replied.

The Base, which is derived from the English translation of the name of radical Islamic terrorist group al Qaeda, is a white supremacist paramilitary group committed to race war. In an affidavit filed with an application for the arrest warrants, the FBI described how Base members discuss their racial terrorism plans online.

“Within The Base’s encrypted chat rooms, members have discussed, among other things, recruitment, creating a white ethno-state, committing acts of violence against minority communities (including African-Americans and Jewish-Americans), the organization’s military-style training camps, and ways to make improvised explosive devices,” the affidavit reads.

Mathews allegedly crossed into Minnesota from Canada around Aug. 19, according to the FBI. After learning that Mathews was hiding in Michigan, Lemley and Bilbrough allegedly drove from Maryland to pick him up, then allegedly drove him back to the mid-Atlantic area on Aug. 30.

On Nov. 4, according to the FBI, Mathews and Lemley rented an apartment in Delaware, according to the FBI. They ordered a part for the gun and ammunition, according to the affidavit, and made regular trips to a Maryland gun range with the functional assault rifle they had assembled. At one point, Bilbrough visited the pair, and the three allegedly discussed the Base’s membership and tried to make the hallucinogen DMT.

On Jan. 11, Lemley picked up hundreds of rounds of additional ammunition and components for body armor, according to the FBI.