The Centers for Disease Control and Prevention on Tuesday advised Americans to avoid all non-essential travel to China in response to the outbreak of a new coronavirus that has taken at least 100 lives.

“While it’s possible that some person-to-person spread with this virus may be detected in the United States, the goal of the ongoing U.S. public health response is to contain this outbreak and prevent sustained spread in this country,” the CDC said Tuesday.

So far all the cases of the virus reported in the U.S. have been linked to travel to China.

The CDC said it raised its travel advisory to level 3, a red alert that advises travelers to avoid unnecessary traveling to a country.

“There is limited access to adequate medical care in affected areas,” the CDC said.

The State Department on Monday issued its highest warning level for travel to the region around Wuhan, the epicenter of the viral outbreak. The State Department also advised Americans to “reconsider” plans to travel to anywhere in China during the outbreak.

The Centers for Disease Control also announced it is monitoring for symptoms of the Wuhan coronavirus at 20 U.S. airports, the agency said on its website Monday. The move to monitor more airports comes as the coronavirus continues to spread and the State Department prepares to evacuate U.S. government personnel and private American citizens from the area.