Three patients in New York state who are suspected of having the much-feared coronavirus are under observation, Gov. Andrew Cuomo announced Friday.

The state Health Department had as many as four cases under investigation, but one proved negative, Cuomo said in a statement.

Citing confidentiality, officials declined to say where the three suspected cases were located.

Cuomo made the announcement shortly after Mayor Bill de Blasio and city health commissioner said there were no cases in New York City — suggesting the state cases were either upstate or in the city’s suburbs.

However, Hizzoner warned that it was just a matter of time before the deadly disease makes its way to New York City, given the city’s major international airports and its large Chinese immigrant population.

The Centers for Disease Control and Prevention announced two confirmed cases in the United States, one in Washington state and one in Chicago.

The Chinese city of Wuhan is the epicenter of the outbreak.

“We are undertaking a wide-reaching and rigorous effort with all stakeholders, including healthcare providers, airports and federal health officials, to put in place the appropriate precautions to keep New Yorkers safe,” Cuomo said. “The symptoms of this virus are very similar to a common cold — if you are concerned that you might be ill, please follow our guidance to protect yourself and others.”

Symptoms of the virus include shortness of breath, runny nose, headache, coughing, sore throat, fever and a general feeling of illness.

State officials also hosted a series of informational webinars for hospitals, local health care providers and medical professionals at New York’s colleges and universities — many of which enroll students from China — to get the word out about the virus.

Stony Brook University, for example, sent health notices to students returning from winter break about the coronavirus.

Precautions include washing hands with soap and water for at least 20 seconds, keeping living conditions in the dorms clean and avoiding close contact with the sick.

“Although there are currently no vaccines available for this disease, there are certain actions you can take to help protect yourself and those around you,” the notice to students said.