Two confirmed cases of coronavirus in Gansu province mean only three Chinese administrative regions remain free from the disease.

Cases have spread out from an epicenter in the central Chinese city of Wuhan, home to 11 million people.

The US Centers for Disease Control and Prevention (CDC) gave Wuhan its highest level of travel notice, recommending travelers avoid all non-essential travel to Wuhan.

The agency gave the rest of the country a level one travel advisory, telling people to "remain alert if traveling to other parts of China.”

The total number of confirmed cases is well over 600 worldwide.