New Yorkers on alert but calm after Boston attacks

"It's just life today after 9/11," an investment manager, who would only give his first name Peter, said as he headed into one of the office towers in Times Square, in the heart of Manhattan.

Police officers were stationed at nearly every corner of the mammoth intersection, which was the site of a failed car bombing in May 2010.

But they were easily outnumbered by the everyday New Yorkers and tourists who refused to be cowed by the specter of terror.

"We cannot sit back and allow the terrorists to instill fear in our hearts. We can't be crippled. This is what they want and I refuse to empower them," said Lucas Ferrara, an attorney who was working at the World Trade Center when it was destroyed on 9/11.

"They're going to see that New Yorkers are resilient, that Americans are resilient, that Bostonians are resilient, and that we will prevail."

Dapperly dressed in a felt hat, Ferrara said he decided to walk 40 blocks to work rather than taking the train as a "very, very small gesture" to show he is not afraid and to enjoy the life-affirming sunshine.

New York Mayor Michael Bloomberg assured residents that police are doing everything they can to keep the city safe.

"As a country, we may not be able to thwart every attack; we saw that yesterday. But we must continue to do everything we possibly can to try," Bloomberg said at a press conference.

"At the same time, we won't let the attack in Boston keep us from our normal daily routines or enjoying the city that we love and that we so painstakingly built."

While there have been "no specific threats" to the Big Apple, the city's police "prepared as if yesterday was a prelude to an attack here in New York," police commissioner Ray Kelly said.

Police increased random bag searches on the city's subway system, patrolled houses of worship and increased their presence at potential landmark targets like the Empire State building.

They also investigated 77 reports of suspicious packages, and Kelly urged New Yorkers to continue to keep their eyes peeled for anything out of place.

The city also has 1,000 police officers dedicated to counter-terrorism and a slew of high-tech aids like chemical, biological, and radiological sensors, as well as a security camera network that can scan license plates and alert police to abnormalities like an abandoned bag.

Other major cities across the country have also boosted security measures, as have airports, sea ports and the national rail service.

Police seemed to be everywhere at Penn and Grand Central stations, and at the Times Square subway stop, which helped calm the nerves of some travelers.

"I feel a bit paranoid, a lot more cautious," Felicia Nina, a 17-year-old high school student from Harlem, told AFP as she rode the train.

A maintenance worker with the transit authority, who said his first name was Kevin, said that while he's "looking around more" for abandoned packages or potential threats, "I don't see fear on everybody's faces, I see alertness."

Back out in the fresh air, Times Square was relatively calm on Tuesday afternoon as tourists posed for pictures, laughed, kissed, and wandered about with seemingly little thought of the terrible attacks which had struck only 200 miles (320 kilometers) away.

"You can't play that game," said Olivier Petit, a Frenchman visiting New York for a week with his son.

Amidst the police cars and yellow cabs, several small crowds formed around newspaper stands which displayed horrific and bloody images of the Boston victims. Overhead, huge electronic signs displayed the latest news, announcing "three dead" in bright red letters.

"People in New York are more sympathetic to people and victims in Boston than they are scared," said Raymond Henderson, 19, who was distributing leaflets for American Eagle.

Convinced that New York has the tools to prevent an attack, Henderson said he's worried about the fact that "there's a lot of hate versus America."

Monday's double bombing in Boston, which President Barack Obama has described as an "act of terror," killed three people, injured 176 and caused panic amid the marathon's tens of thousands of spectators and participants.

Obama said investigators still have not determined a motive for the attack, nor do they know if it was committed by a foreign or domestic group or just a "malevolent individual."