US citizens returning from Hubei province, where the outbreak started, will be quarantined for 14 days.
Almost 12,000 cases of the new virus have been confirmed, most of them in China, since it emerged in December.
More than 100 cases have been reported outside China, in 22 countries.
On Friday, Beijing said the death toll had risen by 46 to 259 - all of them in China and 249 in Hubei.
it emerged that the number of new coronavirus cases worldwide had
overtaken that of the Sars epidemic, which spread to more than two dozen
countries in 2003.
There were around 8,100 cases of Sars - severe
acute respiratory syndrome - during the eight-month outbreak. In total,
774 people were killed by Sars.
On Thursday, the World Health Organization (WHO) declared a global he...