A local asymptomatic infection discovered in the port city of Dandong, in Northeast China's Liaoning Province, was identified as a new sub-lineage of the Omicron variant BA.2.3. No viral sequence with small genomic differences to the strain has been found either in the domestic or in the global data base, the local health authority announced on Tuesday.

The asymptomatic carrier, a resident of Langtou town in Dandong's Zhenxing district, was detected on Sunday. At total of 33 close contacts and 75 secondary contacts were placed under quarantine immediately. All of them tested negative on Sunday and Monday.

According to the local health commission, a new positive case of COVID-19 was confirmed on Tuesday morning. The infection was a recovered COVID-19 patient who was released from quarantine and came from another place to Dandong for work.

Over the past two weeks, as many as 10 different Omicron variants have been identified across the country, including the BA.5 variant detected in Xi'an, Northwest China's Shaanxi Province, the BA.2.12.1 subvariant found in Chengdu, Southwest China's Sichuan Province, the BA.2.38 subvariant found in Lanzhou, Northwest China's Gansu Province and the BA.5.2.1 subvariant in Shanghai, Tianjin and Qingdao in East China's Shandong Province. Most of these variants are imported from overseas.