Mr. Joe Biden made speech at the swearing-in ceremony at the Capitol in Washington on January 20, 2021 (Photo: Patrick Semansky/The Associated Press)

The inauguration ceremony was held in Washinton, DC, attended by 1,000 guests and secured by 2,500 National Guard troops.

Also sowrn in was Kamala Harris, America's history-making vice president, who is the first woman, the first black person, and the first person of South Asian descent elected to the office.

President Joe Biden’s inaugural speech called all Americans to unite to meet the current challenges.

"This is America’s day. This is democracy’s day. A day of history and hope. Through a crucible for the ages, America has been tested anew and America has risen to the challenge. Today, we celebrate the triumph, not of a candidate, but of a cause, the cause of democracy. The will of the people has been heard and the will of the people has been heeded. We have learned again that democracy is precious. Democracy is fragile. And at this hour, my friends, democracy has prevailed."

President Biden said he knows it will be hard for US people to immediately reconcile, but stressed that only unity will enable the US to overcome current difficulties.

"With unity we can do great things. Important things. We can right wrongs. We can put people to work in good jobs. We can teach our children in safe schools. We can overcome this deadly virus. We can reward work, rebuild the middle class, and make health care secure for all. We can deliver racial justice. We can make America, once again, the leading force for good in the world."

Mr. Biden vowed to repair US alliances and engage with the world again.

The leaders of Japan, India, Pakistan, Spain, Italy, Germany, the EU, and Pope Francis, sent their congratulations to the new US President and promised to increase cooperation with the US to deal with shared challenges.

Immediately after the inauguration, President Biden signed 15 executive orders on the COVID-19 pandemic, climate change, and racial inequality, and reversing a number of policies of Donald Trump’s administration. Two orders were aimed at bringing the US back to the Paris Agreement on climate change and cancelling permits for construction of the Keystone XL pipeline.