The oath was administered by Chief Justice John Roberts at the Capitol Rotunda.

Earlier, outgoing President Joe Biden and Trump rode together to the US Capitol for the latter's oath-taking programme after a traditional tea ceremony at the White House along with their wives, Kamala Harris and her successor J.D. Vance and their spouses.

Jill Biden and Melania Trump rode together to the Capitol in a separate car as did Kamala Harris and her successor J.D. Vance.

This is only the second instance of the swearing-in taking place indoors -- the last time was in 1985 when President Ronald Reagan took the oath for his second term.

Earlier, Biden welcomed Trump to the White House for a traditional tea ceremony with two words: “Welcome home”, according to media reports.

Guests for the swearing-in had begun arriving at the Capitol Rotunda where the ceremony took place; indoors instead of the traditional venue outside.

This was only the second instance of the swearing-in took place indoors; the last time was in 1985 when President Ronald Reagan took the oath for his second term.

Trump’s return to the White House is also only the second time for an American President to serve two non-consecutive terms. The first was Grover Cleveland at the end of the 19th century.

The swearing-in was attended by Trump’s nominees to the cabinet such as Marco Rubio, for secretary of state, who is expected to be the first to be confirmed, as early as Monday.

Trump started Monday’s inauguration proceedings by attending a private service at St John’s Church with the incoming first lady Melania Trump, J.D. Vance and wife Usha Vance and some members of the cabinet.

Meta CEO Mark Zuckerberg, Amazon’s Jeff Bezos, Apple’s Tim Cook, Tesla and Space X’s Elon Musk, and Google’s Sundar Pichai also attended the swearing-in ceremony.

Former President Bill Clinton and his wife Hillary Clinton, former President George W Bush and his wife Laura Bush, and former President Barack Obama minus his wife Michelle Obama attended the oath-taking ceremony as is the tradition, which was broken by President Trump who skipped Biden’s inauguration in 2021.