"All illegal entry will be immediately halted and we will begin the process of returning millions and millions of criminal aliens back to the places from which they came."
The speech echoed many of the themes he sounded at his first inauguration in 2017 when he spoke darkly of the "American carnage" of crime and job loss that he said had ravaged the country.
Trump, 78, took the oath of office to "preserve, protect and defend" the US constitution at 12.01pm inside the US Capitol, administered by Chief Justice John Roberts.
Donald Trump has taken the oath of office to become the 47th US president at the US Capitol. (AP PHOTO)
His vice president JD Vance was sworn in just before him.
"The golden age of America begins right now," Trump said after acknowledging former presidents and other dignitaries.
"Our sovereignty will be reclaimed. Our safety will be restored. The scales of justice will be rebalanced," he continued.
"Our top priority will be to create a nation that is proud, prosperous and free."
Trump intends to sign a raft of executive actions in his first hours as president, incoming White House officials said on Monday, including 10 focused on border security and immigration - his top priority.
In addition to declaring an emergency, the president will send armed troops there and resume a policy forcing asylum seekers to wait in Mexico for their US court dates, officials told reporters.
President Donald Trump shook hands with former president Joe Biden after being sworn in. (AP PHOTO)
He will also seek to end so-called birthright citizenship for US-born children whose parents lack legal status, a move some legal scholars have said would be unconstitutional.
The inauguration completes a triumphant comeback for a political disruptor who survived two impeachment trials, a felony conviction, two assassination attempts and an indictment for attempting to overturn his 2020 election loss.
"The journey to reclaim our republic has not been an easy one, that I can tell you," Trump said, before referring to the assassin's bullet that grazed his ear in July.
"I was saved by God to make America great again."
Outgoing US president Joe Biden and vice president Kamala Harris, who lost to Trump in November, were on hand inside the Capitol's Rotunda, along with former presidents Barack Obama, George W Bush and Bill Clinton.
Former Secretary of State Hillary Clinton, who lost to Trump in 2016, arrived with her husband Bill but Obama's wife Michelle chose not to attend.
Numerous tech executives who have sought to curry favour with the incoming administration - including the three richest men in the world, Tesla and SpaceX CEO Elon Musk, Amazon CEO Jeff Bezos and Meta CEO Mark Zuckerberg - had prominent seats on stage, next to cabinet nominees and members of Trump's family.
Elon Musk was among people to have prominent seats on stage during the swearing in of Donald Trump. (AP PHOTO)
Incoming administration officials told reporters Trump will sign an order ending diversity, equity and inclusion initiatives in the federal government on Monday, which is also Martin Luther King Jr Day, a holiday in memory of the country's most famous civil rights leader.
But Trump will not immediately impose new tariffs on Monday, instead directing federal agencies to evaluate trade relationships with Canada, China and Mexico, a Trump official said - an unexpected development that unleashed a broad slide in the US dollar and a rally in global stock markets on a day when US financial markets are closed.
Earlier Trump and incoming first lady Melania Trump arrived at the White House, where Biden and outgoing first lady Jill Biden greeted them with handshakes.
"Welcome home," Biden said.
One more selfie for the road. We love you, America. — President Biden (@POTUS) pic.twitter.com/71k46uGADVJanuary 20, 2025
Shortly before leaving the White House, Biden posted a photograph of himself and his wife.
"One more selfie for the road. We love you, America," he wrote on the platform X on Monday morning.
The photo shows Biden, 82, and his wife Jill, 73, beaming against the backdrop of a snowy garden at the White House.
with AP and DPA
