The Centers for Disease Control and Prevention (CDC) has issued a warning to people traveling within the U.S. as the coronavirus continues to spread.

With several states reporting a growing number of confirmed cases of COVID-19, the CDC warns about crowded airports or other crowded travel locations that may increase the risk of exposure to the virus.

The agency is urging travelers to reconsider their destination and whether or not the coronavirus is spreading at these locations, especially if they have a closed-in setting with little air circulation, where others are sick. These settings could include concerts, sporting events, religious gatherings, movie theaters, shopping malls, and public transportation.

Those that may be more susceptible to contracting the coronavirus include older adults and people of any age that have underlying health conditions such as heart disease, lung disease, or diabetes. The CDC said that these travelers, in particular, should avoid all cruise ship travel and nonessential air travel.

Travelers that are exposed to COVID-19 may be asked to stay in their home to self-monitor and avoid contact with others for up to 14 days.

The CDC is asking people to consider the risk of spreading the coronavirus to others during travel. It is suggesting that people choose to delay or cancel their travel plans. Those that do decide to travel are asked to practice precautions to prevent the spread of COVID-19.

The Department of State has also issued a travel advisory for Americans looking to travel abroad after President Trump issued a 30-day ban on European travel, which begins Friday at midnight.

The Department of State has posted individual Travel Advisories for the most urgent threats from the coronavirus on its website. The agency warns of travel restrictions quarantines, and border restrictions, especially in areas where COVID-19 cases have not been reported as the location may restrict travel without warning.

According to the World Health Organization, more than 132,000 people worldwide have been confirmed to have the coronavirus, with nearly 5,000 deaths reported. The U.S. has over 1,200 people that have tested positive for COVID-19, with 36 deaths reported, the agency said.