The US State Department on Monday issued an upgraded travel warning for China, citing the coronavirus outbreak.

The warning was raised from level two, or "exercise increased caution," to level three, "reconsider travel."

More than 4,600 people have been infected by the virus, and at least 107 other people have died.

Visit Business Insider's homepage for more stories.

The US State Department on Monday issued an upgraded travel warning for China as concerns about a coronavirus outbreak grow.

The warning level was raised from level two, or "exercise increased caution," to level three, "reconsider travel."

More than 4,600 people have been sickened by the virus, and at least 107 other people have died.

The coronavirus, which causes pneumonia-like symptoms, was first observed in Wuhan, a city of 11 million people in China's Hubei province.

Wuhan has been quarantined by Chinese officials, with transportation links to the city suspended. At least 15 other cities in China have also been quarantined or had transit links suspended.

The virus has spread to at least 16 other countries, including the US.

The virus, officially called 2019-nCoV, is thought to have originated in animals — possibly snakes — before jumping the species barrier to humans; the outbreak has been linked to a seafood market in Wuhan that sold live animals. The virus can also be passed from person to person.

US health officials began screening passengers from China at airports earlier this month. The federal government said on Tuesday that it would expand those screenings to more airports around the US.