Passengers wait to depart at John F. Kennedy International Airport in New York, the United States, March 13, 2020. (Xinhua/Wang Ying)

U.S. top infectious disease expert Anthony Fauci said new COVID-19 infections contracted over the Thanksgiving holiday will not become evident until weeks later, making it "very difficult" as the virus could spiral out of control heading into the December holiday season.

WASHINGTON, Nov. 24 (Xinhua) -- Millions of Americans are traveling for the Thanksgiving holiday, ignoring the advice of the U.S. Centers for Disease Control and Prevention (CDC) and health experts to stay at home.

With the recent exponential surge in COVID-19 cases nationwide, the CDC has urged Americans to stay home and not travel for Thanksgiving.

"Travel may increase your chance of getting and spreading COVID-19. Postponing travel and staying home is the best way to protect yourself and others this year," the CDC said in a new guideline on Friday.

The safest way to celebrate Thanksgiving is to celebrate at home with the people you live with, said the guideline.

Yet more than 3 million travelers passed through security at America's airports over the weekend, according to the U.S. Transportation Security Administration.

Passengers wait to depart at John F. Kennedy International Airport in New York, the United States, March 13, 2020. (Xinhua/Wang Ying)

Anthony Fauci, the nation's top infectious disease expert, said he worries that crowds at airports are going to get the country into "even more trouble" than it is in right now.

He added that new COVID-19 infections contracted over the Thanksgiving holiday will not become evident until weeks later, making it "very difficult" as the virus could spiral out of control heading into the December holiday season.

The number of new COVID-19 cases in the United States has skyrocketed to all-time highs recently, averaging more than 170,000 a day, according to the CDC data.

It took only six days for the country to add over 1 million infections to a record high of 12 million cases on Saturday.

A passenger wearing facial mask waits to buy ticket at Grand Central Station in New York, the United States, Feb. 29, 2020. (Xinhua/Wang Ying)

Daily case increase in the United States surpassed 100,000 for 15th consecutive days by Sunday.

More than 144,000 new child COVID-19 cases were reported the past week from Nov. 12 to 19, a 28 percent increase in child COVID-19 cases in the country, according to the latest data of the American Academy of Pediatrics (AAP) and the Children's Hospital Association.

The number of new reported child COVID-19 cases, a 28 percent increase, is by far the highest weekly increase since the pandemic began, according to the AAP.

Nearly 1.2 million children in the United States have been diagnosed with COVID-19 since the onset of the pandemic, according to the AAP.

The United States has recorded more than 12,481,000 cases with more than 258,600 related deaths as of Tuesday afternoon, according to the real-time count kept by Johns Hopkins University. ■