Law enforcement agencies from across the region participated in a full-scale emergency terror drill Wednesday.
The exercise took place at six sites in Washington D.C., Maryland and Virginia, and involved hundreds of police, fire, emergency medical service personnel and volunteer actors, the Metropolitan Council of Governments (COG) said.
Police and SWAT teams in full tactical gear swarmed an area near Nationals Park.
The drill looked so realistic that some Washington Navy Yard employees said it brought back memories of the shooting that killed 12 people in 2013.
"It does bring up that anxiety of 'Oh no, not again,'" said Marry Craddock, who works at the Navy Yard.
People watching the exercise said they appreciated the agencies' efforts.
"It’s always good to have to have a practice. So when the real deal - if the real deal comes, we are prepared," Bonita Pratt said.
"It’s a really good way for different agencies to work together to iron out any kind of kinks to highlight strengths, to figure out weaknesses and to work on those in concert," said Margarita Mikhaylova, a spokesperson for D.C. police.
Before the drill, officials did not release the exact locations of the exercise, but Prince George's County police said to expect an increased police presence around Bowie and Cheltenham. Arlington County police said to expect more law enforcement near The Scalia Law School at George Mason University. In the D.C., the drill was held in Northeast and Southeast.
Residents in those neighborhoods were notified of the exercise.
"We want to make sure we can respond effectively...and efficiently," said Maryland Capitol Park Police Chief Stanley Johnson.