The martial arts event was held outside the White House on President Donald Trump's 80th birthday, and the approximately 4,000-person audience included government officials and business leaders.
The FBI said, after the plans became known, that the gala would be stormed using explosive-laden drones and snipers. However, according to court documents seen by the AP, it is unclear whether the suspected attackers had obtained all the equipment when the plan was foiled by police.
About 20 people are suspected of involvement in the foiled attack. Now two more people have been arrested in the states of Missouri and Washington.
