Donald Trump vowed to usher in a new "golden age" as he took the oath for a historic second US presidential term on Monday.

He painted a picture of an America in decline, claiming that only his hardline policies could restore the nation to its former glory.

In an often divisive address at the US Capitol, the 47th president promised a flurry of executive orders, including declaring a national emergency at the Mexican border and instituting a policy recognizing only two genders.

Trump also embraced a nationalistic tone, emphasizing his extraordinary political comeback. He pledged to impose trade tariffs, rename the Gulf of Mexico the Gulf of America, and "take back" the Panama Canal, which has been controlled by Panama since 1999.

"The golden age of America begins right now. From this day forward, our country will flourish and be respected again all over the world," Trump said in the Capitol, where the inauguration was held indoors for the first time in decades due to freezing weather.

The Republican even suggested he was on a divine mission, stating, "I was saved by God to make America great again" after surviving an assassination attempt at a rally in July.

While promising renewal, Trump harshly denounced what he called a "betrayal" of Americans by a "radical and corrupt establishment" under outgoing President Joe Biden.

"America's decline is over," Trump declared, becoming the oldest president in US history at 78.

Biden, 82, who had earlier hosted Trump and his wife Melania for tea at the White House, watched with a stony expression as his political rival delivered his critique of Biden's single term in office.

'National Emergency'

Trump was surrounded by America's wealthiest and most powerful figures at the inauguration, held in the same building that his supporters attacked in January 2021 as they attempted to overturn the certification of his election loss to Biden.

Elon Musk, the world’s richest man, along with Meta CEO Mark Zuckerberg, Amazon founder Jeff Bezos, and Google CEO Sundar Pichai, all sat in prime seats in the Capitol, alongside Trump’s family and cabinet members.

Musk, who will lead a cost-cutting effort in the new administration, later told a rally that Trump's victory marked a "fork in the road of human civilization."

Former presidents Barack Obama, George W. Bush, and Bill Clinton attended the ceremony with their spouses, though Michelle Obama pointedly stayed away.

Trump will begin his second term with a series of executive orders.

"I will declare a national emergency at our southern border" with Mexico, Trump said to loud cheers from the audience, adding that he would deploy troops to the border and deport "millions and millions" of illegal immigrants.

Trump also stated that his administration would recognize "only two genders, male and female," ending the practice of offering a third gender option in certain government settings, and abolishing diversity programs.

He vowed to withdraw the US from the Paris climate accord aimed at addressing global warming, expand oil production, and encourage more drilling, while scrapping rules intended to promote the purchase of electric vehicles.

Finally, Trump promised to "plant the Stars and Stripes" on Mars.

"I feel on cloud 10," said Gregg Donovan, a 65-year-old from Hollywood, wearing a top hat adorned with a photo of Trump, outside the Capitol after the inauguration.

Biden Pardons

After delivering his concise half-hour inaugural address, Trump quickly shifted to a more informal speech, discussing topics ranging from immigration to his wife's attire, and even repeating his false claim that he had won the 2020 election—an ongoing effort to undermine US democracy.

In a split-screen moment as Trump spoke, an emotional Biden told staff, "We’re leaving the office, but we’re not leaving the fight." He then boarded a final flight to California.

Biden's last acts in office revealed his disdain for Trump, whom he had planned to face in the 2024 election before concerns about his age led him to drop out. Biden preemptively pardoned former officials and family members to shield them from "baseless and politically motivated investigations" under Trump.

Despite the tensions, Biden sought to restore some traditional decorum to the inauguration. After Trump skipped Biden's inauguration in 2021, Biden invited Trump and Melania to the White House for tea.

Trump is just the second president in US history to return to power after being voted out, following Grover Cleveland in 1893. He is also the first convicted felon to become president, due to charges related to paying hush money to a porn star during his first presidential campaign.

Russian President Vladimir Putin congratulated Trump and expressed openness to talks on the Ukraine conflict.

Israeli Prime Minister Benjamin Netanyahu also congratulated Trump, whose team helped broker a ceasefire deal in Gaza.