A new wave of airplane flights carrying hundreds of Americans stuck in China amid the worsening novel coronavirus outbreak were slated to head to the United States as the global tally saw its highest surge in a single 24-hour period, officials said Wednesday.

In conjunction with the U.S. Department of Health and Human Services, the Centers for Disease Control and Prevention (CDC) announced passengers from Wuhan, epicenter of the virus that has killed nearly 500 people in that country, will arrive at four locations. They include Travis Air Force Base in Sacramento, California; the Marine Corps Air Station Miramar in San Diego, California; Lackland Air Force Base in San Antonio, Texas; and Eppley Airfield in Omaha, Nebraska.

“This could be the beginning of what could be a long response,” Nancy Messonnier, director of the National Center for Immunization and Respiratory Diseases at the CDC , told reporters.

Upon arrival, all passengers will be screened and quarantined for up to two weeks to ensure they do not develop symptoms, health officials said. Currently, flights from mainland China are being funneled through about a dozen U.S. airports in accordance with a new U.S. travel ban affecting foreign nationals who have recently been to China.

Word of the flights due from China came on the same day that two previously arranged evacuation flights arrived in California. Meanwhile, Messonnier said Wednesday there had been no new cases of the flu-like outbreak in the United States since a CDC update Monday showing 11 positive cases in five states. But within hours of her call with reporters, health officials in Wisconsin were said to confirm that state's first coronavirus case, bringing the domestic U.S. tally to a dozen.

As of early Wednesday, 76 people were under investigation for possible coronavirus infection in the United States and 206 had tested negative, according to the CDC. Messonnier said that despite more than 800 staff members working to combat the outbreak nationally, the health organization was confident they would “see new cases of the novel coronavirus as people travel back from China.”

Cases have mostly been linked to travel to Wuhan, China, but the outbreak has shaken the global stock market, prompted inter national travel constraints, and left hundreds of Americans and others quarantined on cruise ships and in other secure sites.

To date, the coronavirus has affected at least 24,363 people in mainland China and nearly 200 people across 25 countries—with more than 3,000 new cases in the last 24 hours , according to the World Health Organization . The global death toll has risen to at least 492 people, with the only two fatalities outside mainland China having been reported in the Philippines and Hong Kong.

“In the last 24 hours, we had the most cases in a single day since the outbreak started,” WHO Director-General Tedros Adhanom Ghebreyesus said at a Wednesday press conference, adding that 191 total cases were outside mainland China.

Tedros also announced Wednesday the global health organization had requested $675 million for funding for the next three months—with a portion of the money slated to go toward supporting countries grappling to contain the flu-like outbreak.

“Our message to the international community is ‘invest today or pay more later,’” Tedros said. “We cannot defeat this outbreak without solidarity. Political solidarity, technical solidarity, and financial solidarity.”

Despite the latest surge of new cases, the CDC has maintained that “the immediate risk of coronavirus exposure to the general public is low” and is undertaking several measures to ensure the coronavirus remains low-risk, according to a Wednesday press release.

In the United States, most of the coronavirus cases have been centralized in California, where six people have been confirmed, including two infections in Santa Clara County; two individuals in San Benito County, near Monterey, where a woman was reportedly infected by her husband; and one case each in Orange County and another in Los Angeles County.

Americans with the coronavirus have also been identified in Washington State, Arizona, Massachusetts, and Illinois.