The contagion “represents a tremendous public health threat,” said one federal health official.

At least 34 people in the United States are infected with the new coronavirus spreading from China, federal health officials said on Friday.

Thirteen of the infections were diagnosed in travelers who fell ill after returning from overseas, and 21 in people “repatriated” by the State Department.

More infections are expected among the people who were passengers aboard the Diamond Princess cruise ship and are in quarantine, Dr. Nancy Messonnier, director of the National Center for Immunization and Respiratory Diseases, said at a news briefing.

Because they may have been in contact with infected people on the ship, “they are considered at high risk for infection,” Dr. Messonnier said.

Read more: New York Times