The World Health Organization says it is "getting closer" to declaring a global outbreak of the swine flu virus.

WHO's flu chief Keiji Fukuda says the disease has spread to 64 countries and infected 18,965 people, causing 117 deaths.

Fukuda says the global body is now calling the situation "moderate" rather than "mild" because it is still unclear how serious the virus is.

He says WHO has consulted experts on when to declare the outbreak a pandemic — a global epidemic. Those experts said the severity of the virus should be considered instead of only its geographic spread.