(Reuters) - Bag searches and gun-toting police officers in the New York subway, a watch tower in Times Square and thousands of security cameras are now as ubiquitous in the city as yellow taxi cabs and cosmopolitan cocktails
Although Russian authorities said the attack appeared related to the conflict in the North Caucasus, New Yorkers have lived with the fact their city is a "high value" target for extremist groups since the September 11, 2001, attacks on the United States that felled the World Trade Center.
"Living under that threat, at this point, it has gotten to be a new reality of life," said Dean Kilpatrick, a former president of the International Society for Traumatic Stress Studies. "Whereas most people live their lives pretty reasonably ... it is a kind of chronic stresser that weighs on people as they go about their day to day activities".
New Yorkers have had frequent reminders of the city's vulnerability, most recently with guilty plea of Afghan immigrant Najibullah Zazi to charges that with al Qaeda training he plotted a suicide bomb attack on the subway; and last year when one of President Barack Obama's official planes flew low over the Statue of Liberty for a photo opportunity, triggering a brief panic.
"I feel safe," said retired Pedro Rodriguez, 66, as he waited at a Lower Manhattan subway station on Monday. "But there should be more security down here like at Grand Central station where there are people with machine guns".
The Obama administration has had to reconsider a plan to hold the trials of five men accused of plotting the September 11 attacks, including the alleged mastermind Khalid Sheikh Mohammed, in a court near where the Twin Towers once stood. The proposal drew strong criticism from some in New York because of the cost of ensuring security. Some residents worried it could make them more vulnerable.
Several experts likened New York's heightened anxiety to other places on extremist groups' hit lists, such as London. But some said that unease could not be compared to cities in countries such as Israel, Pakistan, Afghanistan and Iraq where bombings can be part of daily life.
"We live under a constant threat, but it's remained as a threat since 9/11," said Craig Katz, president of the Disaster Psychiatry Outreach, which dispatches volunteer psychiatrists to disaster sites. "I think the omnipresent threat is similar, but the fact that it hasn't become real again makes us worlds apart".
NUMB TO DANGER
While 2009 was the safest year in New York City in decades, with the murder rate down to levels not seen since the early 1960s, authorities have disrupted several extremist plots to cause mass death and destruction in New York.
In 2004 police uncovered a plan to blow up a midtown Manhattan subway station, below a thriving shopping district that includes Macy's department store and just a block from the Empire State Building.
After Zazi plead guilty last month to plotting to bomb the subway, New York's Daily News newspaper wrote in an editorial: "The pattern is clear: Al Qaeda is coming at the U.S. faster than ever, and from multiple directions, often with the help of homegrown fanatics. We stand warned".
Posters asking that New Yorkers "see something, say something" if they spot something suspicious are plastered in subway stations and trains and groups of police cars practice "surging" through city with sirens blazing.
"There are certain things that keep New Yorkers alert," said Charles Strozier, director of the Center on Terrorism at John Jay College. "You have to numb yourself to the danger in order to live your life if you're going to survive with these sorts of threats hanging over you".
"But it lurks in people's minds, able to be easily and immediately activated if something happens," he said.
A 2007 steam pipe explosion in Midtown Manhattan created a towering geyser of debris and sent thousands of people fleeing in scenes reminiscent of the September 11 attacks.
"You will see from time to time how the public's pulse is jumping," said Yuval Neria, director of the trauma and post traumatic stress disorder program at New York State Psychiatric Institute and Columbia University Department of Psychiatry.
Keith Jackson, 34, a consultant who sometimes works in Lower Manhattan, said the site of the World Trade Center was a reminder not to take things for granted, but he said living or working in New York was "an inherent risk" you accepted.
"It's a minor inconvenience for the extra security, but ... now you don't really think about it twice," he said in Times Square. "You always think (New York's a target) but it doesn't necessarily change the way you make any decisions, you're not going to move away, it's just the way it is".
Additional reporting by Basil Katz, editing by Mark Egan and Frances Kerry
Reuters
