The White House has acknowledged the nation does not have enough coronavirus test kits as cases of the disease ticked upwards on both US coasts.
California has declared a state of emergency after announcing its first coronavirus death, bringing the US death toll from the disease to 11.
The death toll from two tornadoes that ripped through central Tennessee has risen to 25, the state's Governor William Lee said on Tuesday.
Joe Biden has won eight of the 14 states that voted to pick a Democratic White House candidate on Super Tuesday, a remarkable rebound for his campaign.
Pete Buttigieg, the former Indiana mayor who made an ambitious run for president, has announced he is ending his campaign for the White House.
Former US vice-president Joe Biden has been handed a huge boost in the race to challenge Donald Trump in November's election.
US President Trump in a news conference on Wednesday said the US was "very, very ready" to handle the coronavirus, as he appointed his vice president Mike Pence to take charge of the outbreak.
Accusers of Harvey Weinstein have welcomed the guilty verdicts in the rape and sexual assault case against the former Hollywood mogul.
Bernie Sanders has cemented his status as the Democratic front-runner to take on Donald Trump in November's US presidential election.
Democratic presidential hopeful Bernie Sanders has condemned Russia for its reported attempts to help his campaign, telling it to "stay out of American elections".
Russia's unmanned Luna-25 spacecraft has crashed into the Moon after spinning out of control, officials say.
Donald Trump has confirmed that he will not take part in Republican presidential debates with his rivals in the race for the White House.