WASHINGTON, Dec. 15 (Xinhua) -- U.S. President Joe Biden said on Thursday that COVID-19 cases "are rising" across the country.

The remarks, which Biden posted on Twitter, came as American families are getting together for the holidays.

The White House is resuming a program to send COVID-19 testing kits to households that request them ahead of a potential winter surge.

A patient arrives in an ambulance cared for by medical workers wearing personal protective equipment due to COVID-19 concerns outside NYU Langone Medical Center on April 13, 2020, in New York. (Photo: AP)

"While COVID isn't the disruptive force it once was, we know that the virus will circulate more quickly and easily as folks gather indoors for the winter holiday season," the official said.

The seven-day average of weekly new COVID-19 cases, according to the U.S. Centers for Disease Control and Prevention (CDC), reached more than 65,000 last week, an increase of nearly 50 percent compared to the previous week.

More than 99 million COVID-19 cases and 1.08 million deaths had been reported in the United States as of Dec. 7, CDC data showed.

In addition to COVID-19, two other viruses -- influenza and respiratory syncytial virus (RSV) -- are also sweeping through the United States.

Several U.S. cities and counties, including New York City and Los Angeles County, are urging the public to wear face masks indoors.

"We are at the brink of another surge," Saju Mathew, an Atlanta, Georgia-based primary care physician and public health specialist, tweeted on Thursday.

"Wearing a well-fitting mask will go a long way as people travel during the holidays, helping protect against the current respiratory viruses," Mathew also wrote.