(CNN) A California-bound flight chartered by the US State Department left the China city at the epicenter of the coronavirus outbreak on Wednesday morning local time, a department spokesman said.

About 240 Americans could be on the flight from Wuhan Tianhe International Airport. It will stop to refuel in Anchorage, Alaska, before arriving early Wednesday at a military base near Riverside, California -- instead of a nearby civilian airport in Ontario, California, as first planned.

The plane will land at March Air Reserve Base instead of Ontario International Airport, officials said. No reason was immediately given for the change in itinerary.

While in Anchorage, passengers will be screened by US Centers for Disease Control and Prevention officials, who will decide if they are healthy enough to continue on to California.

"Any passenger(s) who are found to have cough, fever, or shortness of breath in Anchorage will be further assessed by CDC and DHSS medical experts," a news release from the Alaska DHSS says.

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