A new emergency alert system in the District faltered Sunday, failing to notify residents that the federal government had raised the terrorism threat level for more than five hours after the decision was announced, officials acknowledged yesterday.

Mayor Anthony A. Williams (D) has touted the alert system as an "immediate" information tool for residents, but Sunday's events appeared to highlight what business and community leaders say is a weakness in the District's terrorism response plan: keeping the public informed.

The snag also underscored that although the city has accomplished much since the Sept. 11, 2001, terrorist attacks, much remains to be done.

The city has identified evacuation routes, for instance. But neighborhood plans to assist residents and businesses trapped by an attack are still a work in progress. And though hospitals are better equipped to handle a bioterror attack, officials fear that they won't have enough beds to handle mass casualties.

The Department of Homeland Security has identified public awareness as a top priority. Thomas J. Lockwood, director of the department's Office of National Capital Region Coordination, said the Washington area has made "quantum leaps forward."

"Have we gotten better? Absolutely," he said. "Is there still a lot of work to do? Yes."

Alert DC, the city's emergency notification system, was the high-tech answer to Homeland Security's concern that much of the region had no efficient way to communicate with residents if power outages left them without access to television and radio.

"The question we heard over and over again from citizens is, 'How will I know that something has happened?' " Williams said when the $250,000 system went online last month.

The system is programmed to call all 1.5 million land-line telephone numbers registered in the District with a recorded message. That was not done Sunday, officials said, because the city was not under attack.

The system also can send 18,000 text messages a minute to cell phones, computers, pagers and other electronic devices. In its first terrorism-related test, however, the system was plagued by glitches.

The message wasn't sent out until about 7 p.m., in part because the person responsible for writing and getting it approved had other emergency-related duties, said D.C. Emergency Management Agency spokeswoman Jo'Ellen Countee.

Messages were routed through a virus-scanning system, which bogged down, causing further delays. Ned Ingraham, a senior technology manager, said yesterday that he hopes to fix the problem within 24 hours.

But even if the system had worked as advertised, few people would have received the message: Unlike the land-line phone messages, the text messaging system requires residents to sign up by logging on to www.dc.gov or www.emergencycenter.dc.gov. So far, only about 2,250 people have done so.

The District's efforts to educate the public about its emergency plans have met with mixed success. Leaders hope that a recent $4.9 million grant will allow them to reach more people.

"We have to do a better job at the grass-roots level," said Caroline Cunningham, director of the emergency preparedness task force for the Greater Washington Board of Trade.

The city has distributed a guide with general advice on how to prepare for emergencies. But community and business leaders say that a plan to save lives by organizing neighborhoods in advance of an attack appears to have fallen by the wayside.

The District spent $800,000 to develop the plan, which divides the city into 39 "clusters." In the clusters, organizers are supposed to register volunteers with special skills, such as physicians, and people willing to go door-to-door to provide information and aid or to check on vulnerable residents.

"Experience shows that after a major disaster, police, fire, rescue and other emergency support agencies may not be available to many people during the first 72 hours," the plan states. "A neighborhood that has organized prior to a disaster will know what to do."

But many business and neighborhood leaders said the city has not effectively publicized the plan and has not named cluster coordinators.

"Business owners and property owners and tenants are equally frustrated in this area," said Marcia Rosenthall, executive director of the Golden Triangle Business Improvement District, home to both the World Bank and the International Monetary Fund headquarters. "We'd like some information every now and again from the mayor's office. We'd like to see these plans."

The city's cluster plan "solves nothing, tells you nothing, relates to nothing, and nobody has approved it," said Dorothy Miller, who chairs the elected Advisory Neighborhood Commission in that area.

On Capitol Hill, local leaders are also in the dark. Patty Brosmer, executive director of that area's business improvement district, said that after "stumbling" across the Capitol Hill plan on the city's Web site, she "raised an alarm" with city officials because it contained incorrect information, such as where to find community medical resources. "I was told they were working on it," she said. "We're supposed to get some clarity soon."

Tony Bullock, the mayor's spokesman, said the city has conducted more than 100 community meetings on preparedness. But he said that it "may not be conceivable to get neighborhood-specific plans for every neighborhood" and that city officials never said "that would be done by today."

"It's easy to be critical," he said. "It's also a hell of a lot of work to organize these things, and you can't do everything at once."