BEIJING (AP) — The U.N.'s Food and Agriculture Organization is warning an outbreak of African swine fever in China could jump the border to neighboring countries in Southeast Asia or the Korean Peninsula.

The FAO said in a news release Tuesday that outbreaks have been reported in four different Chinese provinces. It said the distances between each outbreak of up to 1,000 kilometers (621 miles) mean the virus could spread to other Asian countries.

African swine fever poses no direct threat to humans but threatens to devastate China's crucial pork industry.

China is the world's biggest pork producer, accounting for about half the world's population of swine at around 500 million head.

China has culled more than 24,000 pigs and imposed strict quarantine and disinfection efforts in hopes of stamping out the virus.