A senior scientist has warned that the US faces "impending doom" as coronavirus cases and hospital admissions rise across the country.
On Monday President Joe Biden urged state politicians once again to make mask-wearing obligatory in public places.He also promised that by mid-April 90% of American adults would be able to receive a vaccine.
The US has recorded around 60,000 new cases daily for the past week.
The director of the US public health agency, the Centres for Disease Control and Prevention (CDC), was speaking at a White House briefing when she said she was going to go "off script".
"I'm going to reflect on the reoccurring feeling I have of impending doom," Dr Rochelle Walensky said, adding "we have so much reason for hope, but right now I'm scared".
New Covid cases have reached around 60,000 a day in the past week, a rise of around 7%, according to the CDC.