In the wake of the Paris terror attacks, New York's Police Department is quietly expanding training for "active shooter" situations in which terrorists arm themselves with high-powered rifles and open fire.

Commissioner William Bratton says the new training for the nation's largest police force is based in part on lessons brought back from an NYPD team that was sent to Paris and given widespread access to the scene of the shootings.

Bratton says every police officer will be given information to carry in their memo books on how to deal with active shooters.

And he says more officers will be trained like the NYPD's elite Emergency Services Unit, which responds to the most dangerous situations, from shootings to terror attacks.