NEW YORK (CBSNewYork) -- The boost in security was obvious to many commuters around New York City's bridges, tunnels and mass transit hubs Friday morning.
Officials announced Thursday evening there was a "specific, credible but unconfirmed" terror threat against New York City and Washington D.C. related to the 10th anniversary of the 9/11 attacks.
"The information is that they're looking at car bombs in bridges and tunnels," counter terrorism expert Bob Strang told CBS 2. "It could be anywhere."
1010 WINS' John Montone reports: Extra Eyes At Transit Hubs
Police were prominently stationed at the Henry Hudson Bridge toll plaza Friday morning along with NYPD barricades blocking an access road to the Hudson River passenger ship terminal.
Armed officers are also making their presence known at Penn Station, Grand Central, the Lincoln and Holland tunnels and the 59th Street bridge.
People are used to seeing this type of security in the city, but the fact that there is a credible threat of an attack sometime over the next few days has some people's nerves rattled.
"I think they're prepared but still a little nervous," said Strang. "You never know. You just never know."
Strang says the city is ready and has been dealing with these sorts of threats ever since 9/11.
"We're going to see a huge increase in motor vehicle checks, traffic moves," he said.
On Friday, Mayor Michael Bloomberg told New Yorkers to "go back to work. And leave it to the professionals.''
In fact, the mayor made a point of riding the subway to work Friday morning.
"New Yorkers live in a very competitive world. They are very cosmopolitan," Bloomberg said. "They understand that there are threats to our freedoms all the time and New Yorkers get on with their lives."
He added, "Keep in mind, we have threats all the time. On the Internet, every day, there are threats of people, particularly around big sporting events and religious holidays, and around commemorations of things like 9/11. And each time the NYPD, with the FBI, we increase our security, which obviously we have done for this.''
WCBS 880's Rich Lamb reports: Bloomberg Rides The Rails
Many commuters say they trust officials are doing their best to protect us.
"Like they said last night, we have the greatest police department in the world,'' Michael Murphy of Seaford told the Associated Press. "I'm confident they'll do the job.''
"Those guys don't scare me period. Never will," bus rider Eddie Malone told 1010 WINS' John Montone. "If it's going to happen, it's going to happen."
"It's a regular day at the office," said Pat from Queens.
WCBS 880's Paul Murnane reports: Commuters Go About Their Day At Penn Station
Others feel threatened, but many say they're trying to keep it in perspective.
"I definitely feel the worry for us. It's something that we experience every day. You don't know what's going to happen," said one commuter.
"A little scared. I hope it doesn't happen," said Upper East Side resident Sophia Achee. "But a little uncomfortable maybe."
Gov. Andrew Cuomo issued a statement that said "All New Yorkers should be cautious and aware as we prepare to commemorate the 9/11 anniversary. However, there is no reason to panic or allow our spirit of freedom to be dampened as we get ready to celebrate the opening of the Ground Zero site this weekend."
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