Officials stress that there have been no reports of any specific threats against the city.
Police fielded dozens of calls about suspicious-seeming items and briefly evacuated part of LaGuardia Airport on Tuesday. Officials said that there were 135 calls of suspicious packages or suspected bombs from around the time word spread of the explosion in Boston until 5 p.m. Tuesday, almost three times as many as the 48 calls in the same period last year. All the reports were unfounded.
At LaGuardia Airport, wires protruding from a ceiling spurred a call to authorities and about an hour-long evacuation of the airport's central terminal building, according to the Port Authority of New York and New Jersey, which runs the airport. The wiring turned out to be part of a light fixture.
Still, authorities say this kind of reaction was expected after the deadly attacks.
"We prepared for that," NYPD Commissioner Ray Kelly said. "We increased our emergency services officers on patrol."
The major focus includes landmark locations, such as the Empire State Building and World Trade Center site, and transit hubs. Subways and commuter rails are getting an extra dose of protection, and Mayor Michael Bloomberg - and his security detail - took the subway on Tuesday to show that it's safe.
Around the financial district, the security measures looked the same as they always do, but Bloomberg noted Monday that some of the steps will be noticeable - and others will not be.More critical response teams, which are highly visible patrol units that travel with lights and sirens, have been deployed, and authorities are watching live feeds from the NYPD's high-tech camera network in congested areas. The MTA also beefed up patrols, as well as bag inspections. Riders should continue to expect a dramatically heightened state of alert at LIRR and Metro-North hubs, as well as at subway stations. Police say if you have a bag, expect it to be searched, so allow extra time for travel on mass transit. Bloomberg is asking all New Yorkers to focus thoughts and prayers on the Boston explosion victims and their families. "I know I speak for everyone, as did the previous speakers, when I say that our thoughts and prayers go out to the people of Boston," Bloomberg said. "I came from Boston, and the scenes that I saw...on television were just devastating." Bloomberg implored all New Yorkers to remain vigilant and call authorities if they see anyting suspicious.
"But at the same time, we refuse to let cowardly acts of violence stop us from living in our city," he said.
The New York Road Runners, operators of the ING New York City Marathon that was canceled last November following Superstorm Sandy, said security was their top priority.
"We will continue to work hand in hand with the City of New York and the NYPD as we plan for upcoming events," the organization said in a statement.
There are events this weekend - a 5K run/walk to the Sept. 11 Memorial and Museum Sunday, plus a 4-mile race in Central Park.
"We are certainly re-evaluating them in light of the event that took place yesterday," Kelly said.
In terms of size, there is no comparable event to the Boston Marathon in New York until the Five Boro Bike Tour on May 5, which draws considerably fewer people to the city than the annual marathon, canceled in November due to Superstorm Sandy.