New York City was on high alert this week, even before Thursday night's announcement that there was a "credible but unconfirmed" terrorist threat to New York and Washington, D.C. Newspaper headlines screamed about a city on lockdown.
When the Navy SEALS entered Osama bin Laden's compound in Pakistan, they reportedly found documents and handwritten materials referring to the 10th anniversary of the Sept. 11 attacks. Given that information, New York Police Commissioner Ray Kelly told a conference on security and counterterrorism Wednesday: "We have to take precautions as if an actual plot were under way."

The next night Kelly and New York Mayor Michael Bloomberg held a news conference to discuss the threat and the city's response.
"Now the threat at this moment has not been corroborated," Bloomberg said. "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."
By Friday morning, people were already reporting more bag searches and being stopped at vehicle checkpoints all over the city. They noted police in the subways and train stations wearing helmets and bulletproof vests, and carrying assault rifles.
Kelly said there would be "increased focus on tunnels and bridges, and infrastructure in general, as well as landmark locations, houses of worship and government buildings."
Starting Saturday night, 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. According to Kelly there will be "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 skywatch towers will be manned."
Copyright 2020 NPR. To see more, visit https://www.npr.org.