Photo: CFP

Police in Shanghai have started a probe and will pursue criminal responsibility of a confirmed imported COVID-19 case who illegally crossed the border from the Hong Kong Special Administrative Region (SAR) into the mainland, Shanghai authorities said on Friday. 

As of 8 am on Friday, 15,280 people and 551 environment samples related to the case have returned negative nucleic acid test results. Related venues have been disinfected, the Shanghai health authority said via its WeChat account on Friday when replying to a resident's question about the case.

Shanghai reported 13 imported COVID-19 cases on Thursday and no new local cases were reported, according to the Shanghai Health Commission.

One of the patients is a Chinese national living in the Hong Kong SAR who arrived into the mainland from the Hong Kong SAR on February 13, and arrived in Shanghai on February 14 from Zhuhai in South China's Guangdong Province by high-speed train. 

This is the fifth confirmed COVID-19 case of the 15 people who illegally entered Zhuhai from Hong Kong. The previously reported four cases were reported in Chenzhou of Central China's Hunan Province and Guangzhou in Guangdong Province.

Three districts in Zhuhai, South China's Guangdong Province vowed to reward tip-offs as much as 100,000 yuan ($15,786) to combat activities of smuggling and illegal border crossing, the districts' epidemic prevention and control headquarters said on Tuesday.

Zhuhai suspended all flights to Beijing due to epidemic prevention and control requirements of civil aviation from Friday.

Global Times