Daniel K. Inouye International Airport began screening passengers from China on Tuesday as part of stepped-up efforts against the coronavirus at 20 U.S. ports of entry.

But federal officials say there is little risk to the general public here and no need for U.S. residents to don surgical masks, despite a run on them in local drugstores.

“It is unnecessary in the United States,” Health and Human Services Secretary Alex M. Azar II said in response to a question about buying face masks. “The risk to any individual American is extremely low.”

He and other health officials spoke at a media briefing Tuesday in Washington, D.C., that is posted online at the website of the Centers for Disease Control and Prevention. They stressed that while the virus is spreading rapidly in China, it has not been transmitted here.

“Right now there is no spread of this virus in our communities here at home,” said Dr. Robert Redfield, director of the Centers for Disease Control and Prevention.

The five people in the United States who have been identified with 2019 Novel Coronavirus all had “direct contact with Wuhan, China,” where the outbreak began, and did not catch it here, Azar said.

So far, 5,974 cases of the virus have been identified in China, an increase of 1,459 from the previous day, according to the latest figures released by the Chinese government. There have been 132 deaths, all in China.

Most cases have been in the central Chinese province of Hubei, where Wuhan and 16 other cities have been largely locked down to keep the virus from spreading further. The restrictions affect more than 50 million people. Wuhan never had direct flights to Hawaii.

“It’s obviously spreading rapidly within China,” Azar said. “I believe close to 50% of the new cases are outside of Hubei province. … There clearly now is evidence of human-to-human transmission outside of that one province.”

“It is potentially a very serious health issue,” Azar said. “We will take the steps necessary to protect the American people.”

The Honolulu airport’s quarantine station normally screens for ill passengers arriving from anywhere. The expanded policy announced Tuesday focuses on screening and educating people arriving from China. Federal officials said quarantine staffing has been beefed up to handle the flow.

Quarantine employees are working to identify passengers with symptoms of the disease, specifically fever, cough and shortness of breath. They are also warning people to call their medical provider if symptoms emerge later.

Airline crews are also required to report travelers who are ill or display symptoms during flight.

Typically, coronaviruses have incubation periods of two to 14 days, but it could be higher or lower for this virus, Azar said.

“Several of our five patients came into the U.S. before we stood up screening,” Dr. Nancy Messonnier, director of the National Center for Immunization and Respiratory Diseases, said at the briefing. “They didn’t have symptoms at the airport. They recognized they were at risk, and when they got symptoms told their providers.”

The CDC is recommending that travelers avoid all nonessential travel to any part of China.

Eddie Flores, chairman of L&L Hawaii, announced Tuesday that a trip he planned to lead to China on Feb. 13 for a group of real estate brokers from Hawaii has been canceled. They had intended to visit Fuzhou, Zhongshan and Guilin.

“We are very disappointed with the cancellation,” Flores said. “However, several friends called us from Fuzhou and told me that most events and gathering are closed. It is like a ghost city. I guess it is better to stay at home.”

A Japanese plane delivered 20,000 face masks and other protective gear to China as supplies grew short.

Even in Honolulu, face masks were flying off the shelves at Longs Drugs. Outlets in Waikiki, Ala Moana Center and Makiki sold out early Tuesday — although more were expected to arrive. A shipment Monday to the Waikiki store disappeared within two hours.

The coronavirus family includes the common cold as well as more serious illnesses such as SARS (severe acute respiratory syndrome) and MERS (Middle Eastern respiratory syndrome).

Azar said the United States is doing all it can to help tackle the novel coronavirus and that international cooperation goes a long way.

“We basically just need the best public health experts in the world working on it,” he said. “China put the genetic sequencing online. … Within one week the CDC had developed a rapid diagnostic test.”

Messonnier said the test is now available only at the CDC and is being reviewed for efficacy with plans to push it out closer to where the patients are, perhaps within a week or two.

Officials prescribe standard precautions for everyone: washing hands, covering mouths when coughing, and staying home when sick. The CDC has a dedicated page with information on the 2019 Novel Coronavirus at its website, cdc.gov.

The Associated Press contributed to this report.