Photo/Illutration Personnel in protective clothing unload luggages from the airplane carrying U.S. citizens being evacuated from Wuhan, China, at March Air Reserve Base in Riverside, Calif. on Jan. 29. (AP Photo)

RIVERSIDE, Calif. --The 195 Americans evacuated from the Chinese city at the center of the virus outbreak are undergoing three days of testing and monitoring at a Southern California military base to make sure they do not show signs of the virus, officials said Wednesday.

The people flown out of China on a plane chartered by the U.S. government are not quarantined, Dr. Chris Braden of the Centers for Disease Control and Prevention told reporters after the plane landed at March Air Reserve Base.

Authorities said those evacuated, who include U.S. consular employees based in the Chinese city of Wuhan and families with children, are technically not required to stay on the base, but that U.S. officials would discuss their requests to leave the base if any ask to do so before the three days are up, said Dr. Nancy Knight of the CDC.

Authorities initially said there were 201 passengers, but the CDC said later that the higher number included pilots and government employees.

The base 60 miles (96 kilometers) from Los Angeles always has round-the-clock security.

“They are sitting in the middle of a military base," Knight said. "Any discussion around departure would be just that: it would be a discussion.”

Officials could quarantine any of those evacuated on a case by case if officials determine they need to do so, Braden said.

So far, the passengers have said they wanted to stay on the base where they get housing and medical attention and testing for the illness, he said.

“They were very happy to be here, and there was no indication they wanted to leave right away," he said. “They wanted to know their status.”

If they show no signs of the virus and leave the base, they will continue to be monitored by public health officials at their destinations for the remainder of a period lasting 14 days, he said.

Symptoms of the virus include fever, cough, and in more severe cases shortness of breath or pneumonia.

None of the passengers showed signs of having the virus when they were screened before leaving Wuhan, the epicenter of the virus, or when they were screened again during a refueling stop in Anchorage, Alaska.

The jet landed shortly after 8 a.m. at the base. A ground crew dressed in white approached the aircraft shortly after it landed and three charter-style buses parked near the plane. About 40 minutes after landing people could be seen walking from the plane to the first bus, which then departed. Another bus pulled up next to the plane's baggage compartment.

All the passengers already underwent two health screenings in China and were screened twice more in Anchorage by the Centers for Disease Control and Prevention. One passenger received medical attention for a minor injury that happened before boarding the airplane in China, Dr. Anne Zink, Alaska's chief medical officer, told reporters after the plane left.

Some of those expected on the flight from Wuhan were not allowed to board because they did not have documents they needed to enter the U.S. and one person with a fever was also denied boarding, Braden said.

Wuhan is the epicenter of a new virus that has sickened thousands and killed more than 100 people. China has cut off access to Wuhan and 16 other cities in Hubei province to prevent people from leaving and spreading the virus further. In addition to the United States, countries including Japan and South Korea have also planned evacuations.

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