There were more than 100,000 new cases of coronavirus in the US on Wednesday - a record one-day increase.
The figure, reported by the Covid Tracking Project, is accompanied by a steep rise in hospital admissions - suggesting that it is not solely due to increased testing.
More than 1,100 deaths linked to coronavirus were recorded on Wednesday.
The Covid crisis is being overshadowed by tensions over vote counting in the fraught aftermath of the US election.
More than 50,000 people across the US are currently in hospital with coronavirus - an increase of about 64% from early October.
Average daily death rates in the country have also been increasing again, although they are still lower than at the start of the pandemic.
In an interview with the Washington Post newspaper on Friday, commenting on the US nearing 100,00 cases, the country's top infectious diseases expert Anthony Fauci said: "We're in for a whole lot of hurt."
He added that the US "could not possibly be positioned more poorly", with colder weather driving people indoors.
In response, White House spokesman Judd Deere said the comments were "unacceptable and breaking with all norms".
With almost 9.5 million total coronavirus infections and more than 233,000 deaths, the US has both the highest number of cases and the highest total death toll in the world.