Joe Biden has warned “people may die” if his incoming presidential administration continues to be impeded by Donald Trump.
Speaking in Delaware, the president-elect said co-ordination was needed to tackle the coronavirus outbreak.
He called President Trump’s refusal to acknowledge he lost the vote, despite calls to do so from both sides, “totally irresponsible”.
“This is not a game,” former first lady Michelle Obama wrote on social media.
President-elect Biden has 306 votes in the electoral college, surpassing the 270 threshold needed to win.
Yet Mr Trump, a Republican, tweeted on Monday morning: “I won the Election!”