Nassau County police officers held a drill Sunday to practice responding to an active-shooter situation.

The simulation was held at the Merrick Library. SWAT teams and special operations officers trained for several different scenarios by acting out response procedures. Volunteers did their part by playing innocent bystanders.

Officials say the drill had been planned for several weeks, but it took on a new meaning after the terrorist attacks in France.

"Clearly what happened in France last week is an indication that these kinds of practices are very necessary throughout the world today," said Nassau Police Chief Steven Skrynecki. "No one knows when the next event will take place."

The chief adds that there's no intelligence suggesting a terror threat here at home.