Hundreds of quails have died of a "highly pathogenic" bird flu at a farm south of Seoul, but it wasn't immediately clear if it was the deadly H5N1 strain, officials said Monday. The outbreak occurred in Gimje, some 262 kilometers south of the capital, killing about 1,000 quails, an Agriculture Ministry official said. It would take another few days to confirm if the birds' death was caused by the H5N1 virus, the official said on condition of anonymity, citing protocol. South Korea recently saw two outbreaks of the H5N1 virus of bird flu at chicken farms, and killed over 770,000 chickens to try to prevent the spread of the virus. Since ravaging Asia's poultry in late 2003, the H5N1 virus has killed at least 154 people worldwide, according to the World Health Organization. Infections among people have been traced to contact with infected birds, but experts fear the virus could mutate into a form that could create a human pandemic.