COVID-19 cases surpassed 400,000 worldwide on Tuesday, while U.S. cases topped 50,000 as the virus spreads more rapidly across the world.

The total number of global cases now stands at 407,485 as of 1:30 p.m. ET on Tuesday, according to data compiled by Johns Hopkins University. The virus emerged in Wuhan, China, in December. It has since spread to most countries around the world, according to the World Health Organization.

Confirmed COVID-19 cases topped 200,000 last week. In the past three days, more than 100,000 new cases have been identified. The virus has now killed more than 18,200 people around the world, while more than 104,200 people have recovered from COVID-19, according to Hopkins.

While new infections and deaths from the virus appear to be slowing in Italy, new cases surged Tuesday in Spain, where more than 6,000 new cases and more than 500 new deaths were reported.

In the U.S., the virus has infected more than 50,206 people as of 2:15 p.m. ET and killed at least 600 people, according to Hopkins. New York state, which has 25,665 confirmed cases as of Tuesday, according to Gov. Andrew Cuomo, accounts for nearly half of all cases in the U.S.

However, the number of actual cases in the country is likely significantly higher, officials have acknowledged. Testing in the U.S. has been hampered by delays and a restrictive diagnostic criteria that limited who could get tested.

Confirmed U.S. cases passed 5,000 just one week ago. On March 1, there were roughly 100 confirmed cases in the U.S.

Local and state officials in the U.S. have warned that the rapid spread of the virus will put the U.S. health-care system to the test. In New York, Cuomo has called for tens of thousands more hospital beds and ventilators, potentially life-saving devices for hospitalized COVID-19 patients. On Tuesday, he warned other states to prepare for their own epidemics.

"New York is the canary in the coal mine. New York is going first. We have the highest and fastest rate of infection," he said at a news briefing, adding that what's happening in New York will spread to California, Washington and other states from there.

WHO officials said Monday that the spread of COVID-19 is picking up speed around the world.

"The pandemic is accelerating," WHO Director-General Tedros Adhanom Ghebreyesus said at a press briefing from the organization's Geneva headquarters. "It took 67 days from the first reported case to reach 100,000 cases, 11 days for second 100,000 cases, and just four days for the third 100,000 cases."

Global infections topped 300,000 on Saturday, three days ago, according to Hopkins data.