US President Donald Trump takes the oath of office with his wife Melania and son Barron at his side, during his inauguration at the US Capitol in Washington, US, January 20, 2017.[Photo/Agencies]

"Today, we are not merely transferring power from one administration to another or from one party to another, but we are transferring power from Washington, D.C. and giving it back to you, the people," Trump said in his inauguration address.

"From this day forward, a new vision will govern our land. From this day forward, it's going to be only America first, America first," Trump said before dignitaries and hundreds of thousands of spectators attending the inauguration ceremony.

Repeating his campaign slogans, Trump pledged that "together, we will make America great again."

He said the new administration will rebuild infrastructures of the country by following "two simple rules: buy American and hire American."

The new President also said the US will strengthen old alliances and form new ties with countries, while vowing to eradicate "radical Islamic terrorism" from the face of the earth.