Donald Trump, assuming the mantle of 45th president of the United States on Friday, pledged in an often bleak, 16-minute address an "America first" administration that would take power from do-nothing politicians and return it to "forgotten" Americans.
Trump, a combative New York real estate mogul who harnessed a powerful populist message for a deeply divided country in his first bid for public office, took the oath of office from Supreme Court Justice John Roberts.
"The forgotten men and women of our country will be forgotten no longer," he told the crowd as a light drizzle settled over Washington. "And I will fight for you with every breath in my body, and I will never, ever let you down."
In a frequently dark address that Trump said he wrote himself, the new president offered his litany of the nation's ills, including mothers and children trapped in inner-city poverty, rusted factories "scattered like tombstones across the landscape," sweeping crime, gangs and drugs, and a failing educational system.
"This American carnage stops right here and stops right now," he said.
Wearing an overcoat, bright red tie and instantly recognizable by his long, swept-back blond hair, Trump raised his right hand to take the oath, placing his left hand on two Bibles — his own, and one used by Abraham Lincoln in 1861.
Stepping to the podium, he delivered his address to the nation and to several hundred thousand people gathered in front of the Capitol.
"We citizens of America are now joined in a great national effort to rebuild our country and restore its promise for all our people," Trump said. "Together we will determine the course of America and the world for many, many years to come."
He pledged to transfer power from Washington and "to (give) it back to you, the people." He vowed to bring back jobs and to protect the border and drew loud applause by vowing to eradicate "radical Islam."
PHOTOS: Inauguration Day 2017
Trump calls out politicians in address
Trump, surrounded by the elite of Washington establishment, also promised to "no longer accept politicians who are all talk and no action, constantly complaining but never doing anything about (it)."
"The time for empty talk is over," he said. "Now arrives the hour of action."
In assigning blame for such problems, he said that for too long, too few have had power and the people have paid the price.
“Washington flourished, but the people did not share in its wealth," he said. "Politicians prospered, but the jobs left and the factories closed.”
He then drove home the core of his take-charge message: “That all changes starting right here and right now.”
Less than an hour after he finished his remarks by raising a clenched fist, Trump escorted his predecessor, Barack Obama, and now former first lady Michelle Obama, to a waiting helicopter that lifted off and circled the Capitol en route to Joint Base Andrews for a flight to the warmth of Palm Springs, Calif.
After lunch and a round of toasts at the Capitol, Trump climbed back into the presidential limousine to lead the parade along the 1.5-mile route from the halls of Congress to the White House.
Protests turn violent blocks from parade route
PHOTOS: Inauguration Day Protesters
The inauguration drew groups of protesters in several locations across the city. In one confrontation that became violent, two police officers were injured and store windows and ATMs were smashed. Police used pepper spray to control the crowd, some of whom were armed with crowbars and hammers, authorities said. About 90 people were arrested.
WATCH: Protests erupt in DC
New clashes erupted around 2 p.m. ET, as rocks were thrown, police in riot gear assembled and people ran. Police said demonstrators caused "significant damage to a number of blocks."
Major protests were also planned for Saturday, when some 200,000 people were expected to turn out, including a Women's March on Washington.
Choreographed ritual for the peaceful transfer of power
Trump, a 70-year-old billionaire and self-styled "disrupter," was joined at the swearing-in by his wife and children. Also on hand were three of the four living former presidents, members of the Supreme Court and leaders of Congress. In addition, his Democratic rival in the election, Hillary Clinton was in attendance, tweeting that she was there "to honor our democracy & its enduring values. I will never stop believing in our country & its future."
Mike Pence, a former congressman and governor from Indiana, was sworn in as vice president by Justice Clarence Thomas.
Despite a forecast of rain, hundreds of thousands of people wound through a sea of police barriers and metal fences to pack the foreground of the National Mall to witness the handover of power from eight years of Democratic rule to a Republican president.
As the carefully choreographed ritual of the peaceful transfer of power unfolded Friday morning, the Trumps were greeted on the steps of the White House by the Obamas.
Trump stepped from a black limo to shake Obama's hand and embrace the first lady. He then saluted a nearby military aide. With the two wives embracing, the four turned to pose briefly for photos. With both men smiling broadly, Obama waved to the cameras then ushered the Trumps inside for tea and coffee on the South Portico.
After the swearing-in and the ritual drive down Pennsylvania Avenue from the Capitol to the White House, the Trumps will settle in to observe the inaugural parade that passes in front of their new residence.
Obama, Trump take to social media
The historic morning — marking the 58th presidential inauguration since 1789 —began with the president-elect, who spent the night at Blair House, tweeting 7:31 a.m.: "It all begins today! I will see you at 11:00 A.M. for the swearing-in. THE MOVEMENT CONTINUES - THE WORK BEGINS!"
It all begins today! I will see you at 11:00 A.M. for the swearing-in. THE MOVEMENT CONTINUES - THE WORK BEGINS!— Donald J. Trump (@realDonaldTrump) January 20, 2017
The Trumps, with Melania wearing a powder blue Ralph Lauren sheath-style dress with bolero-style jacket and gloves, then left to attend an hour-long prayer service at St. John's Episcopal Church, known as the "Church of Presidents," at nearby Lafayette Square before heading to the White House.
In a sign of the new social media world that Trump has championed, Obama also took to Twitter on Friday morning in likely his last use of the @POTUS Twitter handle as president, tweeting that "It's been an honor of my life to serve you."
It's been the honor of my life to serve you. You made me a better leader and a better man.— President Obama (@POTUS44) January 20, 2017
"You made me a better leader and a better man," he wrote. "I won't stop, I'll be right there with you as a citizen, inspired by our voices of truth and justice, good humor and love." He also gently guided readers over to his post-presidency website, obama.org.
Shortly afterward, Obama could be seen slipping a letter into his Oval Office desk, apparently the traditional missive to his successor, then walked out the door.
As he strode along the colonnade outside the Oval Office, Obama said "of course," when asked by reporters if he felt nostalgic. Asked for any last words to the American people, he said simply, "thank you."
At 10:52 a.m., as moving vans and decorators rushed to transform the Obama White House into the Trump White House, the two couples traveled by limo down Pennsylvania Avenue for the formal swearing-in ceremony that marked the end of an exhaustive and combative 19-month campaign.
Trump, a former reality TV star, stunned the political establishment by sweeping to victory and beating his Democratic opponent, Hillary Clinton. But he takes office with an approval rating of only about 40%.
Former presidents attend, but dozens of lawmakers boycott
In a sign of the peaceful transition, three of the four living former presidents, George W. Bush, Jimmy Carter and Bill Clinton, were on hand for the swearing in. Only 92-year-old former president George H.W. Bush is unable to attend, because of health reasons.
More than 60 Democratic members of Congress, led by Rep. John Lewis, of Georgia, however, boycotted the inauguration for a variety of reasons, including allegations of Russian involvement on Trump's side in the election.
The crowd in prime seats below the podium included at least one anti-Trump protester, Erika Hoel, a 23-year-old from Seattle, who sat quietly before the ceremony began , wearing a bright pink knitted hat.
Hoel, who scored a seat from her member of Congress, said she was staging a "respectful silent protest" of Trump's presidency. She said his rhetoric during the campaign was "vile" and said she is dismayed by Republican post-election efforts to cut off tax funding for Planned Parenthood and to dismantle Obama's 2010 health-care law.
"Everything's that's being repealed with no plan to replace it concerns me," she said.
Thousands of people jammed into the area before dawn, maneuvering through police barriers and metal fences erected to provide tight security.
"I hope everyone gives him a chance," said Jason Jenkins, a broker of surety bonds who traveled from Dublin, Calif., to witness the inauguration. "I'm so hopeful that he's going to create jobs and economic growth for everyone."
Jenkins, who wore a Trump cap and scored a prime seat on the West Front of the Capitol from a lawmaker, said he made a couple of $500 donations to Trump during the campaign but praised the real-estate developer for investing millions of his own fortune into the campaign.
"What I'm most excited about ... is that he doesn't owe his soul to anyone," said Jenkins, 47.
Contributing: Fredreka Schouten, in Washington.