President Barack Obama has taken the oath of office in the Blue Room at the White House to officially begin his second term as President of the United States.

President Obama takes the oath of office at the White House (YouTube)

As his wife Michelle and children Malia and Sasha looked on, Supreme Court Justice Supreme Court Chief Justice John Roberts administered the oath in a quiet ceremony.

Today's subdued ceremonies are a function of the calendar and of the Constitution, which says presidents automatically begin their new terms at noon on Jan. 20. Because that date fell this year on a Sunday — a day on which inaugural ceremonies historically are not held — organizers scheduled a second, public swearing-in for Monday.

Also present for Obama's swearing-in were Maya Soetoro-Ng, President Obama's sister, along with her husband and children, Marian Robinson, Mrs. Obama's mother, Craig Robinson, Mrs. Obama's brother, along with his children, Auma Obama, President Obama's half-sister, along with her daughter, Eleanor Kaye Wilson, godmother to Sasha and Malia Obama, along with her husband and Jane Roberts, wife of Chief Justice John Roberts.

Honoring The Fallen

Earlier, Obama and Vice President Joe Biden jointly placed a large wreath, adorned with red, white and blue ribbon, in front of Arlington's Tomb of the Unknowns. Placing their hands over their hearts, the two leaders stood solemnly as a bugler played "Taps."

President Barack Obama, Vice President Joe Biden, Major General Michael S. Linnington (back L), Commander of the US Army Military District of Washington and Sergeant First Class Chad E. Stackpole (R) participate in a wreath-laying ceremony at the Tomb of the Unknown Soldier (Michael Reynolds-Pool/Getty Images)

From there, Obama joined his family at a church service in downtown Washington celebrating his inauguration as well as Martin Luther King Jr. Day. The president's public swearing-in on Monday coincides with the national holiday marking the fallen civil rights leader's birthday, and Obama has invoked King's memory throughout the lead-up to the inauguration.



The Rev. Jonathan V. Newton, an assistant pastor at Metropolitan African Methodist Episcopal Church, prayed for God to prepare Obama for battle, "because sometimes enemies insist on doing it the hard way."

Tonight Obama and Biden were to address supporters Sunday evening at an inaugural reception.

On Monday, a crowd of up to 800,000 people is expected to gather on the National Mall to witness that event, which will take place on the Capitol's red, white and blue bunting-draped west front.

The Associated Press contributed to this story