Washington Assembles Largest Inauguration Security Force Ever

Two million people? Four million? Bring 'em on.

If, as expected, a record crowd turns out for Barack Obama's inauguration, Washington will be ready with the largest number of security people ever assembled in the nation's capital.

The U.S. Secret Service is overseeing a security force of more than 40,000 people, including 7,500 active duty soldiers, 10,000 National Guard troops and 25,000 law-enforcement officers.

That surpasses the 31,000 troops serving in Afghanistan.

Intelligence officials say there are no specific threats, but they acknowledge that the high visibility of the inauguration, the presence of dignitaries and the significance of swearing in the first black president make it a vulnerable target.

"We have to be prepared for the lone individual who will try to interrupt the event all the way up to a terrorist organization," Secret Service spokesman Ed Donovan told FOXNews.com.

The Metropolitan Police Department will deploy 4,000 officers, and it will have help from an additional 4,000 officers from 99 federal, state and local law-enforcement agencies across the country.

Last week, MPD officers started working six-day weeks with 12-hour shifts in anticipation of the inauguration.

"The great thing about the MPD is we're in the nation's capital, so we're accustomed to dealing with mass scale events," said Traci Hughes, a police department spokeswoman.

"The department is quite capable and accustomed to dealing with crowds. We are very good at preparing for these types of events."

Bridges into Washington and about 3.5 square miles of the capital's downtown will be closed Tuesday. The security perimeter covers more of the city than in previous inaugurations.

Thousands of extra police, military troops and law enforcement agents, including plainclothes officers roaming among the crowds, will be on hand to handle the estimated 2 to 4 million people who are expected to come to Washington.

"This is going to be an historic inauguration," said Sgt. Robert LaChance, a spokesman for the U.S. Park Police. "It's going be an event larger than anything we've seen. We expect to have a large crowd, and we're prepared."

The security effort goes into full effect when Obama starts making his way to Washington from Philadelphia by train Saturday.

Thousands of officers from 40 police jurisdictions will line the 137-mile route. Crowds are expected to gather at numerous spots along the way, including overpasses, parking lots and commuter train stations.