US President Joe Biden on Wednesday said that outgoing president Donald Trump had left him a "very generous" letter in the Oval Office, in keeping with tradition.
"The president wrote a very generous letter," Biden told reporters at the White House.
It was very unclear whether Donald Trump would maintain the tradition of outgoing presidents leaving notes for their successors, after he opted to skip Biden's inauguration.
Trump broke 152 years of tradition by refusing to attend his successor's inauguration.
See In Pics: Joe Biden and Kamala Harris take over the reins of USA
Joe Biden became the 46th president of the United States Wednesday as he was sworn in moments after Kamala Harris took the oath as America's first woman vice president.
"Democracy is precious, democracy is fragile and at this hour, my friends, democracy has prevailed," Biden said before a National Mall that was virtually empty due to the ultra-tight security and a raging Covid-19 pandemic that he vowed to confront immediately.
"We must end this uncivil war that pits red against blue, rural versus urban, conservative versus liberal. We can do this if we open our souls instead of hardening our hearts, if we show a little tolerance and humility and we're willing to stand in the other person's shoes," he said.
"Together we shall write an American story of hope, not fear, of unity, not division, of light, not darkness. A story of decency and dignity, love and healing and goodness."
Biden pushed through a flurry of orders the moment he entered the White House, starting with rejoining the 2015 Paris climate accord, from which the United States was the sole outlier after a withdrawal by Trump, an ally of the fossil fuel industry.
