The United Nations health agency on Wednesday advised travelers to avoid going to Hong Kong and the Chinese province of Guangdong because of a deadly outbreak of a mystery disease.
The World Health Organization said it was taking the action because at least nine foreign businessmen have caught Severe Acute Respiratory Syndrome, or SARS, in Hong Kong and returned with it to their home countries.
"People who are planning to travel to Hong Kong or Guangdong should consider postponing their travel until another time," said WHO infectious diseases chief Dr. David Heymann.
SARS has killed at least 75 people and sickened more than 1,800, the huge majority in China and Hong Kong.
Until now, the WHO had said that travelers could continue to go to the affected areas but should be aware of the symptoms of the disease and seek medical help quickly if they felt ill.
A number of countries already have advised their citizens to avoid the area, but many others simply followed WHO guidelines.
China on Wednesday reported that there had been 361 new cases of the disease during March, with nine deaths, and two more people died in Canada -- a country that was struck by SARS after travelers returned from the region carrying the disease.
Already airlines were reporting that passenger numbers were down on flights to the affected areas, and the alert has had a big impact on Hong Kong business.
WHO has not issued advice to travelers intending to visit other countries hit by the disease. Heymann said the outbreak appears to be under control in Vietnam and work to contain it in Singapore and Canada seems to be succeeding.