WASHINGTON - Shortly before 7 a.m. and 3 p.m. every day, video cameras and banks of television monitors flicker to life at the White House and in small studios at the FBI, the CIA, the Pentagon, the Department of Homeland Security and a handful of the other agencies responsible for trying to track down terrorists who might strike on American soil.
In these twice-daily, super-secret video conferences, begun shortly after the Sept. 11 terror attacks, the agencies are expected to share their latest intelligence on the whereabouts of al-Qaida terrorists and their possible plans for attack.
Administration officials say the intelligence about al-Qaida in the 17 months since the attacks has often been alarming.
But this month the evidence became "downright terrifying," a senior law enforcement official said. He said interrogations of captured terrorists and other intelligence suggested an imminent attack that might involve chemical, biological or radioactive "dirty bombs" aimed at lightly guarded targets such as hotels or apartment buildings.
Two weeks ago, officials said, the intelligence was so frightening and so specific - some information pointed to attacks that were timed to coincide with the end of the hajj, the Muslim pilgrimage that concluded Thursday - that they decided the public had to be notified.
That conclusion set in motion a sequence of events that by late last week had led millions of people to rush to hardware stores to stock up on duct tape and plastic sheeting, with some parents pulling their children out of school and topping off their gas tanks to be ready for a quick evacuation - an expression of public anxiety not seen since the first days after the Sept. 11 attacks and rarely seen since the height of the Cold War.
On Friday, Homeland Security Secretary Tom Ridge tried to calm the public, saying that there was no new intelligence to suggest the need to raise the alarm any further.
But even as he suggested that some people had overreacted - "We do not want individuals or families to start sealing their doors," he said - Ridge insisted that the administration was pleased by how its new color-coded public-warning system was working.
"The federal government, the state and local authorities, and the private sector have all taken very important steps to ramp up protective measures to do whatever they can to prevent a terrorist attack," Ridge said.
The administration's critics, including private security specialists, see the events of the past two weeks very differently, arguing that the government's system for analyzing terrorist threats and sharing the information with the public is not making the public any safer. The critics say it is only frightening them.
"The public is being scared, unnecessarily," said Michael Cherkasky, president of the large private security agency Kroll Inc., who said he had spent much of the past week trying to calm his corporate clients. "These Draconian announcements from the government are taking away any perspective that people should have about their lives."
Within the administration, even the biggest supporters of what is known as the Homeland Security Advisory System admit that the system is more art than science - much more - and that the analysis of frequently scant intelligence and decisions about whether to alert the public to its contents must often be subject to hunch.
If not handled properly, they concede, the system can lead to unnecessary panic, or to public complacency that could be equally dangerous. And they acknowledge that the much ridiculed color-coded system may have added to the public's confusion, with few people understanding the difference between a warning level that is yellow ("elevated") and orange ("high").
"Every day we see information that suggests that terrorists are going to hit some American target," said a senior law enforcement official. "But is it worth creating panic if the intelligence is sketchy, or if there is no real way for people to protect themselves?"
Officials say that whatever the criticism, the new procedures for analyzing threats and making the information public has brought order to the slapdash process that existed in the first days after the Sept. 11 terror attacks, when the administration issued a series of vague terror alerts without offering the public any substantive guidance about how to respond, apart from a repeated call for "vigilance."