(CNN) An American who flew out of China on a chartered flight tried to leave a Southern California military base where authorities have been monitoring nearly 200 people for coronavirus symptoms, health officials said.

The unidentified person has been ordered to stay in quarantine at the March Air Reserve Base until the "entire incubation period or until otherwise cleared," Riverside County Public Health said in a statement Thursday.

The incubation period will be 14 days.

"This action was taken as a result of the unknown risk to the public should someone leave MARB early without undergoing a full health evaluation," the agency said.

Nearly 200 Americans arrived Wednesday at the military base from Wuhan, the epicenter of the deadly coronavirus outbreak in China, and were asked to stay for at least three days so they can be monitored for coronavirus symptoms.

US health officials had said they will not issue a blanket quarantine for the evacuees, but some have agreed to stay at the base voluntarily longer than 72 hours.

Jarred Evans, one of the 195 passengers from Wuhan, said he "will stay as long as I need" at the military base. Earlier on Thursday, US Centers for Disease Control and Prevention officials held a briefing for passengers.

"You're not obligated to leave (when the 72 hours are up), so they're saying that the best thing for you, your people, your family and the community is to stay as long as possible," Evans said.

Evans told CNN he was not aware that a passenger tried to leave the base.

Passengers are taking precautions

The passengers are wearing protective masks and are spending some time outdoors.

"We're all still taking major precautions. So it's not like we're around here hugging each other and shaking hands and things like that," Evans said.

None of the passengers have showed signs of sickness but they will be monitored for fewer and other symptoms at least twice daily, said Dr. Chris Braden of the CDC.

If any demand to go home during the initial 72-hour monitoring period, health officials will discuss their options and may issue an individual quarantine if they believe the person poses a danger of infecting others, Braden said.

More evacuation flights for US citizens in Wuhan will be arranged, the US State Department said. Those flights will leave Wuhan on or around Monday; further details weren't immediately available.

American describes panic in Wuhan

Before landing in the US on the chartered flight, Evans spent more than a week holed up in his apartment in Wuhan as coronavirus raced through the city. During that time, he said, residents sent panicked messages, warning others to take precaution.

"It hit fast and ... it just was very hectic for, like, three days straight," he said. "I got the news from my Chinese friends saying, 'Hey, stay inside. Wear a mask. Don't go outside, stock up on some food 'cause this is going to get serious.' And as you can see, it's very serious."

And through it all, it felt surreal, like a bad dream as the city got cut off from the rest of the nation.

"When you're there and there's no transportation, no trains, no subways, no planes, the military is blocking off each and every aspect of the road. No Ubers, nothing. Mom and pop stores are closed. You think to yourself, like, is this real? Is this a movie? Is this a nightmare?" he said.

The New York-native moved to Wuhan to play American football in a Chinese league. When the US Embassy announced it was evacuating diplomats, their families and some US citizens this week, depending on space availability, he had only five hours to get to the airport, he said.

And when their flight arrived in the United States -- first in Anchorage, Alaska, for fueling before making its way to the military base in California -- there was a huge sense of relief among passengers, mixed with some apprehension that some people may have contracted the virus.

"Everyone was clapping. No one was shaking hands, that's for sure ... but we were clapping," he said.

Passengers need monitoring for 14 days

Evans and the other passengers will be held for three days, but that will not be the end of the monitoring process.

If health officials determine they don't pose a danger and can go home , they will still need to be monitored by local officials for the 14-day incubation period, Braden said. Those staying near the base can choose to remain there for the 14 days.

"If anyone demands to leave right now, that is where all of the partners ... would come together and talk about what needs to be done," said Dr. Nancy Knight, the CDC's director of global health protection. She noted that US marshals are on hand to ensure everyone's safety.

Before they arrived in California, the passengers were also screened in Alaska when the flight landed Tuesday night in an isolated area of the Anchorage airport's north terminal, which handles international flights, airport manager Jim Szczesniak said.

The CDC will work with airport officials to clean the terminal, and there are no international flights scheduled at the airport until May, he said.

US and states work to combat epidemic

As more cases of the virus are confirmed worldwide, the White House announced a new task force that's meeting daily to discuss the threat of the coronavirus.

The task force will help monitor and contain the spread of the virus, and ensure Americans have accurate and up-to-date health and travel information , it said.

Meanwhile, states are pushing for more action.

Washington Gov. Jay Inslee asked US federal health officials to expand screenings to passengers returning to the United States from China at Seattle-Tacoma International Airport, where the country's first confirmed case of the deadly virus entered. Inslee wants the CDC to collect passengers' health history and temperature readings.

"There is a lot we don't know about the virus, it's called 'novel' for a reason," Inslee said. "We know there are multiple infections in China and we hope (the CDC) will extend that (testing)."

In Hawaii, the state closest to the coronavirus outbreak, officials are urging residents to avoid discretionary trips to China.

"Not only because of the health threat but because ... travel is very much disrupted," Hawaii Health Director Bruce Anderson said

There are currently no cases of coronavirus in Hawaii, and officials said there's minimal risk to people on the islands.

The State Department has issued an advisory asking Americans not to travel to Wuhan while the virus has an impact.