New York

NYC deploys 500 more officers for precaution after massacre

  • A woman cries and holds flowers in front of a makeshift memorial to remember the victims of a mass shooting in Orlando, Fla., in New York, Sunday, June 12, 2016. A gunman opened fire inside a crowded gay nightclub early Sunday before dying in a gunfight with SWAT officers. (AP Photo/Andres Kudacki)

    A woman cries and holds flowers in front of a makeshift memorial to remember the victims of a mass shooting in Orlando, Fla., in New York, Sunday, June 12, 2016. A gunman opened fire inside a crowded gay nightclub early Sunday before dying in a gunfight with SWAT officers. (AP Photo/Andres Kudacki)  (The Associated Press)

  • A couple embraces as people gather in front of a makeshift memorial in New York to remember the victims of a mass shooting in Orlando, Fla., Sunday, June 12, 2016.  A gunman opened fire inside a crowded gay nightclub early Sunday before dying in a gunfight with SWAT officers. (AP Photo/Andres Kudacki)

    A couple embraces as people gather in front of a makeshift memorial in New York to remember the victims of a mass shooting in Orlando, Fla., Sunday, June 12, 2016. A gunman opened fire inside a crowded gay nightclub early Sunday before dying in a gunfight with SWAT officers. (AP Photo/Andres Kudacki)  (The Associated Press)

  • Couple hug and kiss in front of a makeshift memorial to remember  the victims of a mass shooting in Orlando, Fla., in New York, Sunday, June 12, 2016.  A gunman wielding an assault-type rifle and a handgun opened fire inside a crowded gay nightclub early Sunday before dying in a gunfight with SWAT officers.  (AP Photo/Andres Kudacki)

    Couple hug and kiss in front of a makeshift memorial to remember the victims of a mass shooting in Orlando, Fla., in New York, Sunday, June 12, 2016. A gunman wielding an assault-type rifle and a handgun opened fire inside a crowded gay nightclub early Sunday before dying in a gunfight with SWAT officers. (AP Photo/Andres Kudacki)  (The Associated Press)

Mayor Bill de Blasio says New York City is deploying more than 500 anti-terrorism officers around the city as a precaution after the deadliest mass shooting in modern U.S. history.

Law enforcement officials were in Penn Station's Amtrak area on Monday with a machine that's used for swabbing bags to check for bomb residue.

Transportation Security Administration officials, police and National Guardsmen dressed in fatigues patrolled the station — a fairly familiar sight since 9/11.

Early Sunday in Orlando, Florida, a gunman opened fire at a nightclub, killing 49 people before police fatally shot him.

De Blasio and Democratic Gov. Andrew Cuomo will attend a vigil Monday at the Stonewall Inn in Manhattan. Hundreds of people gathered there Sunday, with some chanting, "No hate!" and "More love!"