US law enforcement said it had foiled an alleged plot to attack the White House during a crowded mixed martial arts event attended by President Donald Trump.

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

The Department of Justice (DOJ) announced charges against five men and said the plotters planned to fly drones armed with explosives over the event, forcing an evacuation when snipers would fire on "high value targets" in the fleeing crowd.

One of those arrested according to a criminal complaint was Tycen Proper, 19, who was taken into custody on 10 June in Ohio after his mother informed police he had been communicating online with an extremist group.

Mr Proper "allegedly amassed firearms, thousands of rounds of ammunition, and tactical gear at his home in Ohio, and he identified potential targets, including multiple members of Congress," the DOJ said.

Mr Trump on Sunday joined thousands of fans at the White House fights, where a temporary arena dubbed "The Claw" was erected on the South Lawn.

The White House is protected by intense surveillance, fencing, checkpoints, anti-air-attack capabilities, snipers and a permanent group of quick-reaction forces.

"In the days leading up to this weekend, our special agents, mission support personnel, and technical security teams worked around the clock to identify those responsible and hold them accountable," Secret Service Director Sean Curran said on X.

The "UFC Freedom 250" event - which coincided with Mr Trump's 80th birthday - was meant to kick off this year's festivities for the 250th anniversary of the declaration of US independence.

Mr Trump has faced several assassination attempts in recent years, most recently when a gunman attempted to storm a White House press gala he was attending in April.