U.S. coronavirus deaths topped 45,000 on Tuesday, doubling in a little over a week as cases climbed to over 800,000, according to a Reuters tally.

The United States has by far the world's largest number of confirmed coronavirus cases, almost four times as many as Spain, the country with the second-highest number. Globally, cases topped 2.5 million on Tuesday, with North America accounting for one-third of all cases.

Deaths increased by more than 2,600 on Tuesday alone with a few states yet to report.

New Jersey, Pennsylvania and Michigan each reported their highest single-day coronavirus-related death tolls on Tuesday — over 800 between the three states. New York state, the epicenter of the U.S. outbreak, reported 481 new deaths.

Coronavirus-related fatalities in the United States hit a peak of 2,806 on April 15, the deadliest single day of the epidemic.

U.S. cases were at 809,000, up 23,000.

New reported U.S. cases appear to be slowing this week, rising by less than 30,000 a day for the past three days. The United States had a record 35,392 cases on April 4.

Medical experts have warned that increased testing will be necessary for the lifting of stay-at-home measures, which experts say are essential to slowing the spread of the highly contagious respiratory illness. However, the measures have ground the economy to a standstill and forced more than 22 million people to apply for unemployment benefits in the last month.

New York, which accounts for nearly half of the deaths across the country, has taken a cautious stance on reopening businesses and schools.

On Monday, New York City said that concerts and other large events would be canceled through June, a contrast with some southern states like Georgia and South Carolina that are relaxing their lockdowns.