The NYPD has beefed up security and staffing, including at the French consulate, France's mission to the United Nations, and Times Square.
New York Police Commissioner William Bratton said his department is operating as though attacks like those in Paris could happen in New York City. And on Long Island, just outside New York City, officials are increasing police patrols at shopping malls and other large public spaces in the wake of the Paris attacks.
Acting Nassau County Police Commissioner Thomas Krumpter said his department works closely with the federal Join Terrorism Task Force. There are no known "credible threats," he said, but the department's intelligence unit perpetually monitors developments.
Commissioner Bratton in New York City said on MSNBC's "Morning Joe" on Monday that the NYPD is constantly working to thwart attacks in a city that remains among the world's top terror targets.
"It's something that, going back to the events of 9/11, that the police department in the city have constantly been preparing for and trying to protect against," Bratton said. "So far, we've been successful: over 20 efforts have been directed against the city, all of them thwarted so far. We will be watching this one very closely to see what can we learn from it."
The NYPD has beefed up security and staffing, including at the French consulate, France's mission to the United Nations, and Times Square.
"We have long recognized that we are the number one terrorist target in the world, because of all we represent," Bratton said. "Here, we have the financial capital of the world, the entertainment capital of the world, the news capital of the world -- all that they hate, so we are the most likely target."
Bratton said the Paris attackers' use of suicide vests is of particular concern. Officers are trying to learn more about the capability and types of arms used in the vests, as well as what communications tools were used by the attackers.
Bratton said an NYPD team will head to Paris this week to bring back lessons that investigators can use in New York.
This report includes information from The Associated Press.