Kelly, who in the last several years has ramped up the department's counterterrorism operation with hundreds of officers and tens of millions of dollars in equipment, applauded bin Laden's demise.
"The death of Osama bin Laden is a welcome milestone for the friends and families of those killed on 9/11, and for all who remain tenaciously engaged in protecting New York from another attack," said Kelly.
Kelly Sunday night issued a message to all police commands reminding them that while there's no information indicating a specific threat to the city, officers should remain alert following Obama's announcement.
Police officials said special heavily armed Hercules teams will be visible at major transportation hubs and other places in the city.
More than 20 NYPD officers were killed in the Sept. 11, 2001, attacks on the World Trade Center.