The U.S. hit 1 million new Covid-19 cases Monday, according to data compiled by NBC News, underscoring the threat of the omicron variant as the third year of the pandemic gets underway.

Washington, D.C., and Florida have had the largest jumps in new cases in the last two weeks. Covid cases increased by 902 percent in Washington in that time, while cases in Florida rose by 744 percent, according to an NBC News analysis of state and local health data.

The record single-day total could reflect delayed reporting, as a number of states did not announce data on New Year’s Eve and during the holiday weekend.

The Centers for Disease Control and Prevention estimates that the omicron variant of the coronavirus now accounts for up to 95 percent of U.S. test samples that were reviewed last week, according to modeled projections. But the projection could differ from later estimates.

Tedros Adhanom Ghebreyesus, the director-general of the World Health Organization, warned last month that the omicron and delta variants were fueling an alarming trend.

“I am highly concerned that omicron, being highly transmissible and spreading at the same time as delta, is leading to a tsunami of cases,” Tedros said Wednesday at a news conference in Geneva.

However, even as U.S. case counts rose in recent weeks, reported deaths did not appear to be surging — suggesting that the omicron variant leads to a more mild form of Covid-19, especially among people who have been vaccinated.

“The general trend that I’m seeing is, if you’re boosted and you get Covid, you really just at worst end up with bad cold symptoms. It’s not like before, where you were coughing, couldn’t say sentences and were short of breath,” Dr. Matthew Bai, an emergency medicine physician at Mount Sinai Queens in New York City, said late last month.

“There are obviously exceptions — like if you start out with a very weakened immune system, your immune response won’t be as strong with a booster. But in your average person, a booster’s definitely going to make a difference,” Bai said. 

The average number of daily hospitalizations in the U.S. was 93,281 Monday, an increase of 35 percent in the previous two weeks.

In a separate development Tuesday, Maryland Gov. Larry Hogan declared a 30-day state of emergency to combat a rise in Covid cases, mobilizing 1,000 members of the Maryland National Guard to help state and local health officials.