New York police say the threat of a dirty bomb was unsubstantiated, but CBS News correspondent Randall Pinkston reports, the response was emphatic.
No one got a pass: At check points along major traffic routes, officers with radiological sensors scanned cars and mail trucks, city buses – any vehicle that could transport dangerous cargo.
There was also aerial surveillance, plus extra sensors on police patrol boats in the city's rivers and harbor.
First word of the threat came from an Israeli-based Web site quoting an alleged American member of al Qaeda predicting attacks in New York, Miami and Los Angeles.
Terrorism experts say it may be a hoax, but, for America's enemies, it accomplishes a goal.
"It's a cheap way to disrupt us, life is going to be more difficult for residents of New York City today," said CBS News terrorism analyst Randy Larsen. "Traffic will be more difficult. It's something for al Qaeda to do, even if they have no capability whatsoever."
Throughout the summer, officials say there's been heightened chatter from intelligence sources of possible threats. Just last month, Homeland Security Secretary Michael Chertoff said he has a 'gut' feeling that al Qaeda is about to strike.
In July, CBS Evening News anchor Katie Couric asked Chertoff if there was any intelligence that al Qaeda was ready to attack at a moment's notice.
"No specific evidence that we're poised on the brink of an attack," Chertoff responded, "but a recognition – as you see from time to time when cases become public – that there are people in the country who at a minimum sympathizers, if not more, and who we have to keep a very close eye on."
A dirty bomb, if one were to be set off, might not kill many people, but it would damage the nation's sense of security.
"Remember it's not a weapon of mass destruction, its a weapon of disruption," Larsen said.
Officials in Miami and Los Angeles made no adjustments to their normal security arrangements. By late today, New York City had taken down check points, but officials insist they will not lower their vigilance.