Beijing has reported 23 locally transmitted COVID-19 cases since Jan 15 with two clusters of infections having different sources, a senior municipality official said on Friday.

The 23 cases - 18 confirmed patients and five asymptomatic cases - were reported from Haidian, Chaoyang, Fengtai and Fangshan districts, said Pang Xinghuo, deputy director of the Beijing Center for Disease Control and Prevention, at a news conference on Friday afternoon.

According to the epidemiological investigation and full genome sequencing of the virus, the authorities made a preliminary assessment that one infection cluster was triggered by the Omicron strain arriving through an overseas mail. The total number of cases infected with this strain is five, all in Haidian district. "The other cluster was caused by a Delta strain arriving through a cold-chain import. The overall number of infected cases is 18, and it includes 13 confirmed patients and five asymptomatic ones in Chaoyang, Fengtai and Fangshan districts."

According to the center, Beijing reported seven new locally transmitted cases and five asymptomatic ones from midnight to 4 pm on Friday. Among them, two live in Haidian district and the remaining 10 in Fengtai district.

All the new cases in Fengtai work in the cold chain industry or are close contacts of the confirmed cases.

Pang said that cold chain companies and their supervision departments should tighten control and prevention measures to ensure disinfection management and safety control of the goods’ storage, delivery and sales.

Pan Xuhong, spokesperson of the Beijing’s Public Security Bureau, said on Friday that a wholesale businessman surnamed Yang was fined for violating the cold chain regulation, having changed an import label to a domestic one.