Donald Trump has told thousands of roaring supporters that he will usher in a new era of American prosperity when he takes office, taking a victory lap inside a packed Washington arena a day before he returns to power with plans to aggressively reshape US immigration and trade policy.

"Tomorrow, at noon, the curtain closes on four long years of American decline, and we begin a brand new day of American strength, prosperity, dignity and pride," he said.

Trump's "Make America Great Again Victory Rally" took place at Capital One Arena, an indoor hockey and basketball venue that will also host some of Monday's inauguration festivities after forecasts of bitter cold prompted officials to move the planned outdoor events inside.

The inauguration is scheduled for noon local time on Monday, when Trump will take the presidential oath of office inside the rotunda of the Capitol building. Approximately 25,000 law enforcement personnel will be on hand to provide security.

Donald Trump arrives at the rally the day before he is to be inaugurated. – Reuters

Thousands of Trump's supporters packed the Washington arena to celebrate his victory.

Throngs of fans danced to music performance as they awaited Trump's arrival at the Make America Great Again Victory Rally.

The rally resembled the free-wheeling speeches that have been a Trump staple since his first White House campaign in 2016.

The event marks his first major address in Washington since he delivered a speech on January 6, 2021, to his supporters that preceded the storming of the US Capitol.

"This is the greatest political movement in American history, and 75 days ago, we achieved the most epic political victory our country has ever seen," he said.

"Starting tomorrow, I will act with historic speed of strength and fix every single crisis facing our country."

Trump's rally, along with his inaugural address on Monday, could preview the tone he plans to adopt during his second White House term.

In recent weeks, Trump has drawn some concern from foreign allies by musing about taking over Greenland and the Panama Canal and turning Canada into a US state.

Attendees hold up signs as Donald Trump speaks at the rally. – AP

Trump told the roaring supporters in Washington he will impose severe limits on immigration on his first day in office, vowing to swiftly fulfil the central promise of his presidential campaign.

"By the time the sun sets tomorrow, the invasion of our country will have come to a halt," he said to cheers.

Trump repeated his campaign pledge to launch the largest deportation effort in US history, which would remove millions of immigrants. An operation of that scale, however, would likely take years and be hugely costly.

A source familiar with the planning said border security will figure prominently in Trump's first executive orders on Monday, which are likely to classify drug cartels as "foreign terrorist organisations," declare an emergency at the US-Mexico border and move toward reinstatement of the "Remain in Mexico" policy which forces non-Mexican asylum seekers to wait in Mexico for their US court dates.

Trump, Vance lay wreaths at Arlington National Cemetery. – AP

Trump said he'd jump start his agenda with a series of unilateral actions from the White House, telling the crowd: “You’re going to see executive orders that are going to make you extremely happy. Lots of them.”

“Tomorrow we will not waste a single moment,” he vowed later to attendees at a dinner reception.

Trump also said he would "get radical woke ideologies out of our military" and order the military to construct a missile defence shield over the US.

He also promised to reverse the "over-classification" of government documents, a seeming reference to his federal indictment for retaining classified papers after leaving office.

That case, along with a separate federal indictment for plotting to overturn the 2020 election, was dropped by the Justice Department after Trump won in November.

He also pledged to release classified documents relating to the assassinations of President John F Kennedy, his brother Robert Kennedy and civil rights leader Martin Luther King Jr.

Earlier, Trump had breakfast with Republican US senators at Blair House, the guest quarters across from the White House. John Cornyn, Susan Collins, Ted Cruz, Rick Scott and Tim Scott were among the attendees seen leaving the event.

He later placed a wreath at the Tomb of the Unknown Soldier at Arlington National Cemetery outside Washington. Trump saluted the tomb as a military bugler played "Taps."

Ahead of the rally, his fans, many dressed in Trump's trademark red jackets and MAGA hats, waited in a cold, driving rain along several downtown Washington blocks, some chanting "USA! USA!".

Trump supporters line up in the snow. – Reuters

Val Tordjman, 58, had travelled across the country from Denver with tickets to watch the inauguration. When he heard the ceremony was being moved inside, notably cutting the size of the in-person audience, he said: "I felt like crying."

Tordjman said he planned to spend the night on the street next to the arena, despite temperatures forecast to plunge to around 19F (-7C). He said he had yet to see Trump in person.

"This is a once-in-a-lifetime opportunity," he said.

Large swaths of the city around the US Capitol and White House have been blocked off by steel fences since last week and there was a heightened police presence throughout the area.

The indoor hockey and basketball venue will also host some of Monday's inauguration festivities after forecasts of bitter cold prompted officials to move the planned outdoor events inside.

The world's richest man, Elon Musk, who has become a Trump confidant since spending more than $250 million on his campaign, also spoke at the event, along with Vice President-elect JD Vance, Ultimate Fighting Championship CEO Dana White, conservative activist Charlie Kirk and conservative commentator Megyn Kelly.

Supporters of US President-elect Donald Trump gather before a pre-inauguration rally. - Reuters

TikTok CEO Shou Zi Chew planned to attend the rally hours after Trump said he would revive the app's access in the United States when he takes office.

Trump urged companies not to let the Chinese app go dark as a US ban took effect on Sunday. Chew is also expected to join other tech executives at Trump's inauguration.

After his rally, Trump took a break at the Blair House, the president’s official guest residence, before heading to a candlelight dinner with VIPs.

Trump delivers remarks as he attends a candlelight dinner along with his wife Melania at the National Building Museum in Washington. – Reuters

Meanwhile, outgoing President Joe Biden made his last official trip as president on Sunday to Charleston, South Carolina, to mark Martin Luther King Jr Day, the White House said.

He will attend services and speak about King's legacy at Royal Missionary Baptist Church.

Biden and his wife Jill will travel to Santa Ynez, California after attending Trump’s inauguration, the White House said.

They will depart the Capitol after the ceremony and attend a farewell event with former staffers at Joint Base Andrews outside of Washington before boarding an Air Force plane for the trip.

The plane will be known as “Special Air Mission 46” – for the 46th president – and not “Air Force One”, since Biden will no longer be the sitting president after noon. The Bidens previously vacationed in Santa Ynez over the summer after Biden ended his bid for reelection.