BEIJING (Reuters) – A new outbreak of African swine fever has been detected in China’s northeastern Liaoning province, the agriculture ministry said on Thursday, the province’s third case this week.

The latest outbreak was found on a farm with 1,353 pigs in the city of Dalian. The fever killed 11 pigs and infected 20 others, the Ministry of Agriculture and Rural Affairs said on its website.

The frequency of outbreaks in the region has intensified concerns that the highly contagious disease is spreading fast among the world’s largest pig herds.

Authorities have banned the transport of live pigs and products to and from the infected area, the statement said.

Dalian is the province’s third city with a confirmed outbreak after the swine fever was detected this week in Anshan and Yingkou.

(Reporting by Hallie Gu and Tom Daly; editing by Darren Schuettler)