In yet another grim development amid the raging coronavirus pandemic, the US reported an all-time number of single-day confirmed cases, according to health authorities.

In its latest update on Saturday, the US Centers for Disease Control and Prevention (CDC) said the country registered a record high 403,359 new cases and 2,756 deaths, reports Xinhua news agency.

As of Sunday morning, the US still accounts for world's highest number of cases and deaths at 17,631,293 and 316,006, respectively.

Saturday's data brought the seven-day average daily case increase to a record-high of 238,923 cases, and the seven-day average daily death increase to over 2,500.

There are a record 114,751 people currently hospitalised with the virus, according to latest data of The Covid Tracking Project.

"Seventeen days into December, this month is already the second deadliest of the pandemic," the project said on Twitter.

Over 42,500 coronavirus deaths has been reported across the nation in December so far, according to the project.

The University of Washington's Institute for Health Metrics and Evaluation, a key Covid-19 model, projects the national daily death toll to continue increasing to a peak of over 3,750 in mid-January.

The model projects 562,000 cumulative deaths on April 1, 2021, which represents 262,000 additional fatatlities from December 14 to April 1.

The soaring cases, deaths, hospitalisations come amid massive vaccine rollout in the country.

The US Food and Drug Administration (FDA) on Friday authorised American drugmaker Moderna's Covid-19 vaccine for emergency use across the country.

It is the second Covid-19 vaccine that received FDA's emergency use authorisation in the country, following the first one developed by American drugmaker Pfizer in partnership with German company BioNTech.

An independent CDC vaccine advisory group voted on Saturday to recommend Moderna's Covid-19 vaccine for people 18 years old and older.

Packages of the Moderna vaccine are being packaged Saturday for delivery on Monday, said Gustave Perna, chief operating officer of Operation Warp Speed, on Saturday.