China's postal service has ordered workers to disinfect international deliveries and urged the public to reduce orders from overseas after authorities claimed mail could be the source of recent coronavirus outbreaks.
China, where the virus first emerged in late 2019, has stuck to a strict policy of targeting zero Covid cases even as the rest of the world has reopened.
But the country is now battling multiple small outbreaks, including one in Beijing as the capital prepares to host the Winter Olympics.
In recent days, Chinese officials have suggested that some people could have been infected by packages from abroad, including a woman in Beijing whom authorities said had no contact with other infected people but tested positive for a variant similar to those found in North America.
China Post on Monday published a statement ordering workers to disinfect the outer packaging of all international mail "as soon as possible" and requiring employees handling foreign letters and packages to receive booster vaccine shots.
The postal service also asked the public to reduce purchases and deliveries from "countries and regions with a high overseas epidemic risk" and said domestic mail should be handled in different areas to prevent cross-contamination.
The coronavirus is spread through small liquid particles exhaled by infected people.
Both the World Health Organization and the US Centers for Disease Control have said the risk of being infected from contaminated surfaces -- known as fomite transmission -- is low and becomes less likely as time passes.
The CDC has said there is a 99 per cent reduction in virus traces left on most surfaces within three days.
But China is not willing to take any risks, even more so ahead of next month's Winter Olympics.
The country uses strict local lockdowns, mass testing and people tracing health apps to stamp out infections as soon as cases are detected.
Millions have been confined to their homes in multiple cities in recent weeks after cases of both the Delta and Omicron coronavirus variants flared.
Recent infections have been detected in areas that receive a high volume of international goods, including in the eastern port city of Tianjin and the southern manufacturing region of Guangdong.
China reported 127 new locally transmitted Covid cases on Tuesday.