BEIJING -- Pork prices in China edged up last week, official data showed.

From May 9 to 13, the average pork price tracked by the Ministry of Agriculture and Rural Affairs was 20.67 yuan (about $3.1) per kg, up 3.2 percent week on week. The price was 15.4 percent lower than a year ago.

China has introduced a three-level early-warning system to raise the alarm for excessive ups and downs in hog prices.

Livestock farms and households are advised to make reasonable decisions for production and operation to maintain the stability of hog production capacity.