An unprecedented level of security will frame President Bush's second inauguration, with officials planning to use thousands of police officers from across the country, new screening technology for guests at the inaugural and a military contingent that could include a combat brigade of as many as 4,000 troops.

Security is always tight on Inauguration Day, but it will be magnified for the first inauguration since the terrorist attacks of Sept. 11, 2001. Law enforcement officials have been preparing for months to protect U.S. and world leaders and citizens who attend.

Organizers are planning a traditional inauguration capped by a parade down Pennsylvania Avenue and the usual evening balls. As tens of thousands come to Washington to watch the Jan. 20 swearing in, the city will be filled with military personnel, FBI agents in full SWAT outfitting, snipers on rooftops and scores of bomb-detecting dogs.