Urban Shield trains first responders in Boston

Approximately 2,000 police officers, fire officials, medics and other first responders took part in the Urban Shield training program on Saturday in Boston as part of a security training exercise.

Urban Shield, a training program started in the Boston area in 2011, conducted 24 hours of simulations to train officers to respond to hostage situations, school shootings, explosives and a rescue from a confined space, the Boston Globe reports.

"We saw in the marathon, it's critical for the bomb squads, the SWAT teams, (Emergency Medical Services), to be coordinated in what they're doing, to be able to talk to each other," Rene Fielding, the director of the city's office of emergency management, said, according to the Boston Globe.

In one simulation, a volunteer acting as a disgruntled civilian with a pretend firearm took six mock elected officials hostage. Eight SWAT team members burst into the room to try to find and arrest the gunman, ensure civilians inside the chambers were not a threat and free the elected officials.

Five SWAT teams cycled through each training site on Saturday.

Police planned a drill in 2013 in which a domestic terrorist organization planted bombs around the city. Two months before the training, two real bombs went off near the Boston Marathon finish line, killing three and injuring hundreds. The drill was canceled by organizers, the Boston Globe reports.