More than 250 personnel from the FBI and local fire and police departments worked through the night at South Coast Plaza Thursday practicing how they'd respond to a terrorist attack.
The FBI coordinated the drill that tested multiple law-enforcement agencies and other first responders on how well they work together.
SWAT and rescue teams ran through responses to a range of scenarios during the exercise that started after South Coast Plaza closed and ran from about 10 p.m. to 4.m.
Costa Mesa, Irvine, Newport Beach and Huntington Beach police all took part in the drill. The Costa Mesa Fire Department, Orange County Sheriff's Department Orange County Fire Authority also participated.