Donald Trump on Wednesday skipped his successor Joe Biden's inauguration and exited the White House for the last time as the US president to board a flight to his Mar-a-Lago estate in Florida, which will be his permanent home after he failed to win his re-election bid.

Joe Biden, hours after being sworn in as the 46th President, will send a comprehensive immigration bill to Congress which among other things proposes to eliminate the per country cap for employment-based green cards, a move that would benefit hundreds and thousands of Indian IT professionals in the US, whose current wait period for legal permanent residency runs into several decades.

President Donald Trump has pardoned former chief strategist Steve Bannon as part of a late flurry of clemency action benefiting nearly 150 people, including rap stars and former members of Congress.

China's highest-profile entrepreneur, e-commerce billionaire Jack Ma, appeared on Wednesday in a video posted online, ending a 2 1/2-month disappearance from public view that prompted speculation about his status and his business empire's future.

Joe Biden, in his maiden address to the nation soon after being sworn in as the 46th President of the United States, would deliver a forward-looking speech built around the theme of unity, advisors close to the President-elect said.

Four years after he left the Beltway for his hometown in Delaware, Joe Biden returned to Washington DC a day before his swearing-in as the 46th President of the United States on Wednesday with the message of unity and the enormous task of healing a bitterly divided country.

 A powerful earthquake struck in northwestern Argentina near the border with Chile, shaking people in both countries, but there were no early reports of damage or injuries.

Gunmen fired on a car in northern Kabul on Sunday, killing two women judges who worked for Afghanistan's high court and wounding the driver, a court official said.