http://news.bbc.co.uk/1/hi/world/americas/8018356.stm
A new flu virus suspected of killing up to 60 people in Mexico has the potential to become a pandemic, the World Health Organization's chief says.
Margaret Chan said the outbreak was a "serious situation" which needed to be followed closely.
Ms Chan cut short a visit to the US and returned to Geneva for urgent talks.
Health experts say tests so far seem to link the illnesses in Mexico with a new swine flu virus that sickened eight people in the southern US.
The WHO's new emergency committee is now meeting - though health officials say it may be premature to advise against travel to Mexico.
The committee will be discussing whether to declare a public health emergency, and whether to raise the global pandemic alert level.
The WHO says it does not know the full risk yet.
It is advising all member states to be vigilant for seasonally unusual flu or pneumonia-like symptoms among their populations - particularly among young healthy adults, who seem to be the most affected in Mexico.