Saturday marks the beginning of activities leading up to the Inauguration of U.S. President Barack Obama.

Four years ago, the president and his wife began the tradition of a National Day of Service on Inauguration weekend.

On Saturday, President Obama and Vice President Joe Biden and their families will continue that tradition, joining Americans in all 50 states at local service events.

The president and vice president will ask all Americans to make ongoing volunteer commitments in their communities.

Later Saturday, Michelle Obama and Jill Biden will host the Kids' Inaugural Concert, a event paying special tribute to military spouses and children.

President Obama will be sworn into office twice – once on Sunday and again on Monday.

On Sunday, the U.S. leader will be officially sworn into office at a private ceremony in the White House, meeting the constitutional requirement that he take the oath on January 20.

Mr. Obama will repeat the procedure during a public ceremony at the U.S. Capitol on Monday January 21, which also marks the federal holiday honoring the birth of the civil rights leader Dr. Martin Luther King. At the public event, the president will take the oath of office with his hand placed on two Bibles, one owned by President Abraham Lincoln, the other by Dr. King.

Mr. Obama's Inauguration on Monday will be followed by a parade and Inaugural parties.