WASHINGTON (AP) — Declaring “our work begins today”, President Barack Obama vowed to “finished what we started” four years ago as hundreds of thousands of inauguration-goers gathered on the historic National Mall in anticipation of his oath-taking for a second term.

“Let’s go,” Obama tweeted Monday morning as he began the day of inaugural celebrations.

The president was cheered in the streets as he returned to the White House following a morning church service. At midday, He was to speak to a huge crowd on the Mall and millions more watching on television, hoping to set an optimistic tone for a divided nation seeking solutions to economic woes at home and conflict overseas.

The fanfare is extending across the nation’s capital, including the traditional inaugural parade and a pair of glitzy formal balls.

Obama and his family, along with Vice President Joe Biden, arrived at St. John’s Episcopal Church on a crisp and clear morning. Known as “The Church of the Presidents”, St. John’s is located just across from the White House on the other side of Lafayette Park. Pew 54 is known as “the president’s pew” and is reserved for the commander in chief whenever he attends.

The centerpiece of Monday’s festivities is Obama’s inaugural address. The president will be urging lawmakers to find common ground and will preview his second-term goals, including immigration reform, stricter gun-control laws and an end to the war in Afghanistan.

Obama is also facing fresh concerns about terrorism in North Africa. In the midst of the inaugural celebrations, a U.S. official said two more Americans died in Algeria, bringing the U.S. death toll from a four-day siege at a natural gas plant to three. Seven Americans survived, the official said.

Washington largely shelved its partisan fighting for the three days of inaugural celebrations. Obama, perhaps seeking to start fresh with lawmakers in his second term, invited several members of Congress to the White House before his swearing-in, including the Republican leaders he has been at odds with for the past four years: Senate Minority Leader Mitch McConnell, House Speaker John Boehner and House Majority Leader Eric Cantor.

Pressing matters await the president and Congress once the celebrations subside, including three looming fiscal deadlines. Obama will also need help from a reluctant Congress if he hopes to fulfill his promise to sign comprehensive immigration reform and tighten gun laws in the wake of last month’s school shooting in Newtown, Conn.

The mood surrounding Obama’s second inaugural is more subdued than it was four years ago, when the swearing in of the nation’s first black president drew 1.8 million people to the Mall. Still, organizers were expecting up to 700,000 to attend Monday’s events, which would make it the largest second-term inaugural in history.

At least one public viewing area on the National Mall was full two hours before the president’s swearing-in, and the crowd spread from the Capitol to the Washington Monument.

The weather forecast was encouraging, to a point. High temperatures were predicted for the lower 40s during the day, with a slight chance of rain and snow showers in the afternoon and flurries later.

Security was tight across Washington, with several streets near the White House and Capitol Hill closed off. Humvees and city buses were being used to block intersections. Volunteers fanned out near the Mall to help direct the crowds.

Lawmakers and other officials slowly trickled onto the platform on the West Front of the Capitol where Obama was to be sworn in. Former Senate Democratic Leader Tom Daschle and former GOP House Speaker Newt Gingrich sat next to each other on the folding chairs as they awaited the festivities.

David Richardson of Atlanta and his two young children were among the early crowds heading to the National Mall Monday even before sunrise.

“We wanted to see history, I think, and also for the children to witness that anything is possible through hard work,” Richardson said.

Wendy Davis of Rome, Ga., was one of thousands of inaugural attendees who packed Metro trains before sunrise headed for the Capitol and parade route. Davis came four years ago as well but was among the many ticketholders who couldn’t get in because of the massive crowds. She was determined to get in this time.

“I thought I was early last time but I obviously wasn’t early enough,” she said.

By 8 a.m. thousands of people were also waiting in security lines that stretched a block to gain access to the spots along the parade route that were accessible to the general public without a special ticket.

The cold weather was easily tolerated by Marie-France Lemaine of Montreal, who received the trip to the inaugural as a birthday present from her husband. She headed up an Obama advocacy group in Quebec that cheered on the president from north of the border.

“The American president affects the rest of the world,” she said.

The president was officially sworn-in shortly before noon on Sunday, in keeping with the Constitution’s mandate that presidents begin their new term on Jan. 20. But because inaugural ceremonies are historically not held on Sundays, the public celebration was pushed to Monday, coinciding with the birthday of late civil rights leader Martin Luther King Jr.

Condoleezza Rice, who served as secretary of state under former President George W. Bush, called on Obama to put electoral politics aside in his second term if he hopes to accomplish those objectives.

“It requires now a kind of humility and a reaching across the aisle,” Rice said on CBS “This Morning. “And reaching across the aisle, by the way, means reaching out to Americans who may not have voted for him.”

Following his swearing-in, Obama will attend the traditional luncheon with lawmakers before joining marching bands and floats in the inaugural parade, which winds its way from Capitol Hill to the White House.

The president and first lady will then slip into formalwear for two swanky inaugural balls. That’s far fewer than the 10 they attended after the 2009 inauguration, though this year’s events are still expected to draw up to about 40,000 people.

The centerpiece of Monday’s activities was Obama’s inaugural address. Aides said he would make the case that the nation’s founding values can still guide the country through changing times. He is not expected to outline specifically policy proposals, saving them instead for his Feb. 12 State of the Union address.

Some Americans, weary after four years of shaky economic news, implored Obama to focus on patriotism, not politics, in his remarks.

“I’m just hoping for a nice eloquent speech that makes people feel good about being an American,” said Sean Payton, a 32-year-old Democrat from Highland Ranch, Colo.

Monday’s celebrations bring to a close three days of inaugural fanfare across Washington, including a day of service, a wreath-laying at Arlington National Cemetery, and a concert honoring military families.

The quirk in the calendar meant Obama would end up being sworn in for his second term twice. Sunday’s ceremony was an intimate gathering at the White House, with only a dozen family members on hand to witness Chief Justice John Roberts administer the oath of office.

Obama placed his hand on a Bible used for years by Michelle Obama’s family. On Monday, he’ll take the oath using two — one owned by King and one by Abraham Lincoln.

Vice President Joe Biden was also to be sworn in for the second term a second time Monday. Biden took the oath of office Sunday at the Naval Observatory in northwest Washington. Justice Sonia Sotomayor, appointed by Obama as the first Hispanic to serve on the Supreme Court, administered the oath to Biden, who placed his hand on a Bible his family has used since 1893.

Ahead of his swearing-in Sunday, Obama, along with Vice President Joe Biden, solemnly honored the nation’s fallen soldiers during a wreath-laying ceremony at Arlington National Cemetery. On a crisp, sun-splashed morning, Obama and Biden placed a large wreath adorned with red, white and blue ribbon, in front of Arlington’s Tomb of the Unknowns. Holding their hands over their hearts, the two leaders stood motionless as a bugler played taps.

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Associated Press writers Darlene Superville, Matt Barakat, Alan Fram, Donna Cassata, Jim Kuhnhenn and Mary Clare Jalonick contributed to this report.

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Copyright 2013 The Associated Press.