More security for Obama's inauguration than troop force serving in Afghanistan

The security measures will be unprecedented on Tuesday as Barack Hussein Obama is sworn in as the 44th US president and America's first black head of the state.

Millions are expected to make the pilgrimage to see him place his left hand on Abraham Lincoln's burgundy velvet-bound Bible to take the inaugural oath.

The US 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, FOX News reported.

That surpasses the 31,000 American troops serving in Afghanistan.

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

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," FOX news quoted Secret Service spokesman Ed Donovan, as saying.

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.

Bridges into Washington and about 3.5 square miles of the capital's downtown will be closed on 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 2-4 million people who are expected to come to Washington.

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