Fireworks go off as America's Justin Gaethje celebrates after defeating Georgia's Ilia Topuria during UFC Freedom 250 mixed martial arts event on the South Lawn of the White House in the early morning hours Monday. Pool photo by Saul Loeb/UPI | License Photo

June 16 (UPI) -- The FBI said it blocked a planned attack that targeted the UFC Freedom 250 event at the White House on Sunday.

FBI Director Kash Patel said Tuesday that the FBI learned of the plan on June 10 through Signal chats. The plan included 23 people who lived outside of the area of Washington, D.C.

"Multiple individuals are now in custody and allegedly planned attacks were stopped cold," Patel posted on X.

Two sources told CBS News that the plot included using explosive-laden drones to hit buildings in the area and snipers to attack the crowd as they tried to run. There was a planned "second wave" involving storming the White House gate.