WASHINGTON, Dec. 2 (Xinhua) -- The United States is facing the toughest time amid the COVID-19 pandemic, as a surge in hospitalizations strains hospitals nationwide, the head of the U.S. Centers for Disease Control and Prevention (CDC) warned on Wednesday.

"The reality is December and January and February are going to be rough times. I actually believe they're going to be the most difficult time in the public health history of this nation," CDC Director Robert Redfield said during a livestream event with U.S. Chamber of Commerce Foundation.

Earlier outbreaks of the coronavirus were concentrated on some areas of the country, and medical workers and equipment could be transported to the hotspots. But now, all parts of the country are facing rising infections and hospitalizations, Redfield said.

The number of U.S. COVID-19 patients who currently remain in hospitals reached 100,226 on Wednesday, exceeding the threshold of 100,000 for the first time since the onset of the pandemic, according to the COVID Tracking Project.

About 90 percent of U.S. hospitals are in the red zone, the director said, adding "I do think unfortunately before we see February, we could be close to 450,000 Americans dead from this virus."

The United States remains the nation worst hit by the coronavirus with over 13.9 million cases and 273,300 fatalities, according to Johns Hopkins University.