Bryan Omar Roa, 24, of Calimesa, and Michael Alan Thomas, 32, of Pinon Hills were arrested on Saturday, the day before the fight, and have since made their initial court appearances.
The FBI searched both of their homes and recovered multiple firearms and large quantities of ammunition. Court documents allege one suspect admitted to helping plan the attack and encouraging others to participate.
The FBI said the alleged terror plot involved at least 19 people and included plans for explosions and gunfire. According to an unsealed FBI affidavit, the plan involved setting off explosions using drones near the event and then shooting guests as they evacuated.
Authorities say five people have been arrested so far, including Roa and Thomas, who allegedly planned to target politicians and wealthy attendees.
Federal investigators say the group had been communicating for at least a month online. Among them was 19-year-old Tycen Proper, who was living at his parents' home in Ohio, according to authorities.
Authorities allege Proper used $3,000 of graduation money to purchase guns, tactical vests and thousands of rounds of ammunition for the attack.
The alleged plot came to light after Proper's mother overheard conversations on encrypted chats and phone calls and contacted police, according to court documents.
The FBI's court filing revealed that in those communications, the group - described as strangers claiming to be ex-military and Christian-based - discussed grievances about government corruption, the handling of the Epstein files and concerns about data centers consuming water in communities. Investigators say the group hoped a coordinated attack would tear down the U.S. so it could be built up again.
Authorities say the plan included designated sniper locations, meeting points and discussions of safe houses. The Secret Service has not said how close the group came to executing the attack.
"Look, it was a serious threat," said Secret Service Deputy Director Matt Quinn. "We take all threats of a large nature very seriously, and we investigate them until we can validate 100% that it's no longer a threat. It was an active plot and it's ongoing. Just because we're done with 'Freedom 250,' or that particular event, doesn't mean we're going to stop. There are still suspects at large, and we're going to work it until everyone has been identified."
The investigation also highlights ongoing concerns about drone-related threats. The White House World Cup task force says all 78 matches in the U.S. have counter-drone technology. Los Angeles is set to host eight matches.
During Friday's Team USA match, the FBI seized three drones. In Miami and Atlanta, authorities recovered a combined 35 drones. Officials described those incidents as involving "more idiots than evil doers," referring to individuals violating restricted airspace rather than plotting attacks.
Authorities say the investigation is ongoing.