Donald Trump sworn in as 45th President of the United States

Donald Trump has pledged to put America first and lead a “great national effort” to rebuild the country after being sworn in as its 45th President.

The 70-year-old billionaire took the oath of office on the west steps of the US Capitol in Washington, bringing down the curtain on the presidency of Barack Obama.

The tycoon, who has never held public office before, is now the most powerful leader on the planet.

There has been unrest on the streets of Washington before and after the inauguration ceremony, with black-clad demonstrators smashing shop and car windows, setting fires in the street and police making more than 90 arrests.

Hundreds of thousands of people packed onto the National Mall to witness one of the most remarkable transfers of power in American history.

Among them was Hillary Clinton, his opponent in November’s election.

At an inaugural lunch after the ceremony, Mr Trump led a standing ovation for Mrs Clinton and her husband Bill, telling the audience he has “a lot of respect for those two people”.

Mr Trump is now making his way to the White House as part of the inaugural parade down Pennsylvania Avenue, amid heavy security.

He stepped out of his presidential limousine, nicknamed “The Beast”, a couple of times to briefly walk along the route, and was joined by Mrs Trump and their 10-year-old son Barron.

In his inaugural address, Mr Trump promised to transfer power from Washington to the people.

Mr Trump said 20 January would be remembered as “the day the people became the rulers of this nation again”.

“The forgotten men and women of our country will be forgotten no longer,” the new President said.

Mr Trump added: “From this day forward it’s going to be only America first.

“We must protect our border from the ravages of other countries. I will fight for you with every breath of my body and I will never let you down.”

Continuing the populist tone of his victorious campaign, Mr Trump said that a “small group” in Washington had “reaped the rewards of government while the people have borne the cost”.

“Washington flourished but the people did not share in its wealth,” he said.