Federal authorities have charged five men accused of plotting a mass-casualty attack targeting government officials and others attending last weekend's UFC Freedom 250 event on the White House grounds.

According to the Justice Department, the suspects allegedly planned to use drones armed with explosives to trigger chaos and force an evacuation before sniper teams opened fire on "high-value targets" in the fleeing crowd.

The FBI uncovered the alleged plot and made arrests in Ohio, Missouri, Nebraska and California as part of a multi-state operation. Officials said the investigation remains ongoing.

"The FBI, our law enforcement partners and our U.S. Attorneys did what they do every day to make America safe through quick response and vigilance," Acting Attorney General Todd Blanche said in a statement Tuesday. "We will take immediate and aggressive action to identify and prosecute those who incite and plan acts of violence."

FBI Director Kash Patel said agents learned of the threat on June 10 and moved quickly to stop it before the event.

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

The defendants were identified as Tycen C. Proper, 19, of Ohio; Bryan Omar Roa, 24, of California; Michael Alan Thomas, 32, of California; Daniel K. Eskridge, 32, of Missouri; and Abraham Hermosillo Alvarez, 31, of Nebraska.

Court documents allege the group began communicating about an attack as early as March before moving discussions to encrypted messaging platforms.

Investigators say the suspects discussed using explosive drones, sniper positions, escape routes and potential targets, including members of Congress and other government officials.

According to prosecutors, Proper told investigators he participated in planning the attack and had amassed firearms, ammunition and tactical gear.

Searches of the defendants' homes allegedly uncovered rifles, handguns, ammunition, communications equipment and other tactical materials.

Authorities allege Roa and Thomas exchanged messages about obtaining drones and explosives, while Thomas discussed organizing operational teams and conducting weapons training.

Prosecutors also allege Eskridge participated in discussions about targeting lawmakers and other prominent figures.

Alvarez, who allegedly used the alias "Shepherd," is accused of helping direct the operation by sharing maps, drone launch sites, sniper locations and extraction plans.

Secret Service Director Sean Curran said the agency remains focused on protecting President Donald Trump and the executive mansion amid what he described as a sharp increase in threats against protected officials.

"Protecting the President of the United States and the White House grounds is priority number one for the U.S. Secret Service," Curran said in a statement. "The landscape has changed, and as a result we have seen a dramatic rise in threats against our protectees."

If convicted of conspiracy to commit murder, the defendants could each face a maximum penalty of life in prison and a $250,000 fine.