"The response to shooters of this magnitude, mass shooters, cannot be vigils. It must be legislation," Adams said, questioning the availability of automatic weapons.

A man with a rifle killed an off-duty New York City police officer and three other people before taking his own life at a Manhattan office tower on Monday, according to officials.

The person, who did not immediately know the victims’ conditions, was not authorized to publicly discuss the ongoing investigation and spoke to the AP on condition of anonymity.

Officials said the gunman fatally shot himself after his attack, which set off a chaotic scene that rippled out into the heart of Manhattan during rush hour.

“I want to extend my profound sympathies to all of the victims and their families, and to the brave NYPD cops who today lost a brother,” NYPD commissioner Jessica Tisch said a press conference on Mon...