Despite clod weather, an unprecedentedly large crowd is gathering in Washington on Tuesday to witness the historic inauguration of Barack Obama as the 44th president of the United States.

According to official estimates, as much as 2 million people are expected to gather around the Capitol, White House and Lincoln Memorial by noon when Obama takes oath of office.

The official ceremony of the inauguration of U.S. President- elect Barack Obama has already started on the west front of the U. S. Capitol with musical prelude.

The musical performance include those of the United States Marine Band, the San Francisco Boys Chorus and the San Francisco Girls.

Meanwhile, members of the Congress and other special guests began filling the seats overlooking the stand where the swearing- in of Obama will occur.

Obamas and his wife Michelle began the day by attending a prayer at the St. John's Episcopal Church near the White House.

They then met President George W. Bush and his wife Laura for talks at the White House.

The swearing-in will begin around 1630 GMT, with Biden taking oath first, followed by Obama's swearing-in and inaugural speech.

Some of the inauguration audience will be more than 1.6 kilometers from the swearing-in ceremony, watching on giant TV screens erected along the National Mall.

Thousands arrived before daylight Tuesday in standing-room-only trains.

They carried blankets and wore Obama scarves to ward off the wind chills of minus 10 degrees Celsius.

Visitors wandered around the Mall on Monday night, snapping pictures and shooting video of the Capitol and monuments.

The inauguration day actually began at 4 a.m. for many as those without tickets made a land grab on the Mall, rushing to stake out positions for the ceremony.

In his approximately 20-minute speech, Obama will say America has been hurt by a "me-first" mentality that contributed to the current economic crisis, aides say, and he will call on individuals -- as well as corporations and businesses -- to take responsibility for their actions.

After a formal farewell to President George W. Bush and lunch with congressional leaders, Obama will head up Pennsylvania Avenue to the White House, where he and his family will watch the inauguration parade from a reviewing stand.

The new president and first lady will then close the night by attending 10 official inaugural balls.

Inauguration events have already drawn record crowds.

A crowd attending an inauguration concert last Sunday was estimated between 300,000 and 400,000 and stretched from the Lincoln Memorial all the way to the Washington Monument, which stands at the midpoint of the National Mall.

While Secret Service Director Mark Sullivan said there was "no credible threat" to the inauguration events, a security cordon has been put in place around the city's core, turning much of downtown Washington into a pedestrian-only zone.

In addition to Secret Service, the security effort will involve 8,000 police officers from the District of Columbia and other jurisdictions, 10,000 National Guard troops, about 1,000 FBI personnel, and hundreds of others from the Department of Homeland Security, the National Park Service and U.S. Capitol Police.

Another 20,000 members of the National Guard are ready to respond if there is an emergency.

(Xinhua News Agency January 20, 2009)