At least four people with the virus crossed border and travelled on to other mainland cities
Some Chinese cities have offered rewards for information about people smuggling after 15 individuals illegally entered Zhuhai, in southern Guangdong province, by boat from Hong Kong.
It is not clear if they were Hong Kong residents or Chinese nationals attempting to return home from the territory. According to Chinese media reports, at least four of them had Covid-19 and later travelled to other Chinese cities and provinces.
Shanghai health authorities also confirmed on Friday morning that new cases in the city included a Chinese national who had travelled from Hong Kong to Zhuhai on February 13, and then took a high-speed train to Shanghai on February 14.

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Fences and other fortifications along Hong Kong’s long land border with Shenzhen, Guangdong’s second-largest city, were originally built to stop illegal immigration from China into the territory. It is also easy to travel by boat between Hong Kong and many cities in Guangdong, whose long coastline and river networks are difficult to police.