Dr Rochelle Walensky, head of the United States Centers for Disease Control and Prevention (CDC) has cautioned that the US faces "impending doom," as Covid-19 cases and hospital admissions surging in the country.
Dr Walensky announced that she was going "off script" during a White House briefing, reports the BBC.
"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".
For the past week, the United States has seen about 60,000 new cases every day.
Dr Walensky said that she did not want the United States to experience another increase in cases and deaths, as many European countries have.
According to the CDC, new Covid cases have reached around 60,000 every day in the last week, an increase of around 7%.
According to the New York Times, cases have risen especially quickly in Michigan and the country's northeast, including Connecticut and New York.
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.
Speaking in a TV address from the White House President Biden issued a plea to state governors to re-introduce laws that require citizens to wear masks.
Coronavirus rules in the US vary state-by-state, with some governors ordering much stricter restrictions than others.
"If we let our guard down now, we can see the virus getting worse, not better," Biden said.
CDC reported that more than one in five adults and almost all Americans over the age of 65 are completely vaccinated.
Biden also mentioned the United States' national vaccination program's success, claiming that it was ahead of schedule.
He vowed that by 19 April, 90% of American adults would be registered for a vaccine and will have access to a vaccination centre within five miles of their homes.