The Centers for Disease Control and Prevention on Thursday confirmed 20 new cases of COVID-19 over 24 hours, bringing the United States total to at least 149.

At least 49 of those cases are people who were evacuated from Wuhan, China, the epicenter of the outbreak, or the Diamond Princess cruise ship, the CDC said, adding that the data was current as of 4 p.m. Wednesday. At least 30 are travel-related infections, while 17 were caused by person-to-person spread. U.S. health officials are also investigating 53 other cases with no clear source of the infection, the CDC said.

The CDC said it's tested 1,526 people for the flu-like virus as of Wednesday. That does include testing being done at state and local public health laboratories, which began this week, the agency said.

Earlier in the day, New York City Mayor Bill de Blasio confirmed two new cases of COVID-19 — a man and a woman with no known connection to other people who have the virus.

The World Health Organization is urging nations to "pull out all the stops" to fight COVID-19 as it continues to spread outside of China, the epicenter of the outbreak.