GUY RAZ, host: Even before the news broke of a possible terrorist threat this weekend, security preparations in New York City were higher than ever. City on Lock Down screamed one headline. Here's NPR's Margot Adler.
MARGOT ADLER: When the U.S. Navy SEALs entered the compound of Osama bin Laden in Pakistan, they reportedly found documents and handwritten materials with references to the 10th anniversary of 9/11. New York Police Commissioner Ray Kelly told a conference on security and counterterrorism on Wednesday.
RAY KELLY: Given that, we have to take precautions as if an actual plot were under way.
ADLER: New information that there was a possible terror threat involving New York or Washington, D.C., led Commissioner Kelly and Mayor Michael Bloomberg to hold a news conference Thursday night. Mayor Bloomberg.
Mayor MICHAEL BLOOMBERG: Now the threat at this moment has not been corroborated. I want to stress that. It is credible, but it has not been corroborated. But we do live in a world where we must take these threats seriously, and we certainly will.
ADLER: People are already reporting more bag and backpack searches, being stopped at vehicle checkpoints all over the city. They are noting police in the subways and train stations wearing helmets, bulletproof vests and carrying assault rifles. Again, Commissoner Ray Kelly.
KELLY: There will be increased focus on tunnels and bridges and infrastructure in general as well as landmark locations, houses of worship and government buildings.
ADLER: Starting tonight, there will be a heavily guarded frozen zone around the World Trade Center site, which will extend several blocks in each direction. Traffic will be diverted, and only people with credentials will be allowed in the area. Thousands of police officers will be mobilized.
KELLY: Counter snipers, bomb technicians. Police divers will be inspecting the peers, pilots will be in the air, officers with radiation detection equipment, plainclothes officers to conduct surveillance, and our sky watch towers will be manned.
ADLER: Besides hundreds of cameras trained on the World Trade Center site as well as downtown, midtown and elsewhere, police will be monitoring license plate readers, manhole covers will be inspected and sealed, and the NYPD will be working closely with the Secret Service since President Obama and former President George W. Bush will be attending. The Port Authority of New York and New Jersey, which oversees ports, airports, tunnels, bridges and the World Trade Center site, has canceled all leaves.
Even on a normal day, the security situation in New York City is far different than it was 10 years ago. At a conference bringing law enforcement and private security officials together, James Waters, the assistant chief of the NYPD's Counterterrorism Bureau, talked about the integration of some 2,000 public and private sector camera feeds.
JAMES WATERS: These video feeds as well as data from 140 fixed and mobile license plate readers located throughout Lower Manhattan are monitored around the clock by NYPD personnel and private sector security representatives.
ADLER: In summary, security preparations are intense. As for the main ceremony at the World Trade Center site, churches will toll their bells. And unlike in past years, there will be six, not four, moments of silence. The first, as always, at 8:46 when the first plane struck the North Tower. But the plane crash in Shanksville and the attack on the Pentagon will also be noted with ceremony and silence. Margot Adler, NPR News, New York.
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