China on Friday confirmed it has now imposed travel restrictions on 14 cities, home to tens of millions of people, and pledged to build a new hospital within six days in Wuhan, the epicentre of a deadly virus that is sweeping across the country and through Asia.

The number of cases of the new coronavirus, which causes respiratory problems, has jumped to 830 and the death toll risen to at least 26, with two fatalities now reported outside of Wuhan, in Hubei province and the northeastern province of Heilongjiang, which borders Russia and Mongolia.

On Friday, the US confirmed its second case of the disease. The 60-year-old woman returned from Wuhan with the coronavirus, US health officials told local media. The first case was recorded earlier in the week in Washington State.

Wuhan, a city of 11 million, was suddenly quarantined on Thursday morning, with residents given a 10am deadline before road, rail and air transport links were severed indefinitely in an effort to contain the virus, which is a similar pathogen to Severe Acute Respiratory Syndrome (SARS) and can spread between humans.

A day later, a total of 18 cities in central Hubei province suspended some public transportation over the coronavirus outbreak, the Global Times reported on Friday.