President Biden said on Friday that he would extend the national emergency that was first declared in March 2020 in response to the coronavirus pandemic. The additional authority had been set to expire on March 1.

The decision, contained in a letter from Mr. Biden to Congress that the White House made public, comes as a wave of coronavirus cases driven by the highly transmissible Omicron variant recedes in the United States, and many states and localities ease pandemic restrictions.

But the pandemic is taking a continuing toll on the country. As of Friday, more than 75,000 Americans were hospitalized with the virus. Deaths, which lag case counts by as much as several weeks, are increasing in 14 states, and remain at almost 2,300 a day nationally.

“The Covid-19 pandemic continues to cause significant risk to the public health and safety of the nation,” Mr. Biden wrote in the letter. “More than 900,000 people in this nation have perished from the disease, and it is essential to continue to combat and respond to Covid-19 with the full capacity and capability of the federal government.”

A national emergency conveys special powers. It frees the federal government from abiding by some legal constraints, allowing it to spend additional money and more easily take certain actions.

The pandemic emergency would have expired had Mr. Biden not alerted Congress of his intention to extend it.

President Donald J. Trump first declared the pandemic a national emergency on March 13, 2020. Mr. Trump said that extra measures were needed to combat the virus, which at that time was known to have infected 1,645 people in the United States — a number that now exceeds 78 million.