Washington: Donald Trump was sworn-in as the 45th President of the US, ushering in a new era that he vowed would shatter the established order and reverse a national decline he deemed as an "American carnage".
"I will fight for you with every breath in my body, and I will never, ever let you down," Trump told hundreds of thousands of rain-soaked admirers and onlookers on Friday in a 16-minute Inaugural Address from the West Front of the Capitol here.
"America will start winning again, winning like never before. We will bring back our jobs. We will bring back our borders. We will bring back our wealth. And we will bring back our dreams," the New York Times reported citing Trump as saying.
"This American carnage stops right here and stops right now," Trump said
He arrived at the White House for the first time as President just before 5 p.m., following a day of tradition marking the power shift in the nation's capital.
In a ceremony on the flag-draped West Front earlier on Friday, Trump placed his left hand on a family Bible and another that belonged to former President Abraham Lincoln and promised to preserve, protect and defend the Constitution.
As light rain began to fall on a crowd stretching toward the Washington Monument, Trump took the oath of office from Chief Justice John Roberts with the new First Lady, Melania, CNN reported.
At age 70, Trump became the oldest president sworn in for the first time and the first born in New York since Franklin D. Roosevelt.
"From this day forward, a new vision will govern our land, from this day forward, it's going to be only 'America first! America first!'"
And he told Americans listening to the address: "You will never be ignored again."
Former Presidents Barack Obama, George W. Bush, Bill Clinton and Jimmy Carter attended the ceremony. Hillary Clinton, whom Trump defeated in the November election, was also in the audience.
Before the swearing-in, Trump and his family attended a private church service at St. John's Episcopal Church, known as the church of the Presidents.
The Obamas greeted Trump and the new First Lady at the North Portico of the White House before hosting them for tea, CNN reported.
Obama wrote a letter to Trump and left it on the Resolute desk in the Oval Office, as outgoing presidents typically do for their successors. As Obama left the Oval Office for the final time, he was asked whether he had any words for the American people.
"Thank you," Obama responded.
Trump attended a joint congressional inaugural luncheon in the Capitol before heading back to the White House.
Halfway along Pennsylvania Avenue, Trump's vehicle stopped and the new first couple walked hand-in-hand past the cheering crowds.
After taking office, the US Senate confirmed two cabinet nominations - James N. Mattis as defence secretary and John F. Kelly as secretary of homeland security - but Democrats temporarily held up Mike Pompeo's confirmation as CIA director, an announcement expected later on Monday, The New York Times said.
Trump did not waste any time and issued orders freezing new regulations from recent weeks and ordering agencies to "ease the burden" of the Affordable Care Act (ACA) or the Obamacare during the transition from repealing to replacing the law.
Meanwhile, there were protests in Washington D.C. which led to the arrest of 217 demonstrators with 6 policemen injured. Violence broke out as the demonstrators smashed shop windows and burned a limousine.
Anti-Trump protests also took place in New York, Berlin, London and Berlin.
The day came to an end with three inaugural balls.
The first was the Liberty Ball held at the Walter E. Washington Convention Centre that was attended by supporters who donated to the inauguration or purchased tickets, the New York Times reported.
The First Couple made their entry amid applause. Melania was dressed in an ivory evening gown by designer Herve Pierre with a white ruffle cascading down the front while Trump was in a tuxedo and bow-tie.
The couple then shared their first dance as the White House's new tenants to Frank Sinatra's "My Way".
Vice President Mike Pence and his wife Karen, as well as the couples' children joined them on the stage, The Washington Post reported.
Minutes later, they repeated the ritual at the Freedom Ball. There, Trump addressed the crowd, declaring "We will not be taken advantage of anymore" and even asking the audience "should I keep the Twitter going? It's a way of bypassing dishonest media."
The last was the Armed Services Ball, had a video call with US troops located in Afghanistan's Bagram Airbase.
The airbase personnel took turns congratulating Trump on his victory.
Melania Trump also addressed the crowd. "Thank you all for your service," she said. "I'm honoured to be your First Lady. We will win. And we will make America great again."
The First Couple danced to a rendition of Whitney Houston's "I Will Always Love You." Then, per tradition, they danced with service members.