The number of coronavirus patients in U.S. hospitals breached 50,000, the highest level in nearly three months, as a surge in infections threatens to push the nation’s health care system to the edge of capacity.

U.S. coronavirus cases crossed the 9 million mark, rising by 1 million in two weeks as the world’s worst-affected country faces a resurgence in the pandemic just ahead of elections.

The number of new Covid-19 cases rose 11% in the United States last week compared to the previous seven days, with infections spreading rapidly in the Midwest, which reported some of the highest positive test rates, according to a Reuters analysis.