China's rapidly growing postal delivery industry, closely tied to the nation's economic and social development, has become a new avenue for espionage activities, according to a statement released by the Ministry of State Security on Tuesday.

The ministry disclosed three types of espionage cases related to the delivery sector on its official WeChat account, highlighting the increasing threat to national security.

In one case, classified publication materials were leaked through the postal service. The national security hotline, 12339, received a tip about a potential leak involving classified materials. An investigation led authorities to a suspect identified by the surname Zhang, who had been compromised by foreign intelligence agencies. Zhang, exploiting his access to sensitive publications, provided these materials to foreign agents via delivery services. Zhang was sentenced to 10 years in prison for leaking multiple confidential documents.

Another case involved the shipment of chemical powder that endangered research security. A domestic research institution received a suspicious chemical powder from a foreign institution under the pretext of a collaborative research project. A staff member, uncertain about the powder's composition and purpose, contacted national security agencies. The investigation revealed that the powder could be used as a catalyst in chemical experiments on harmful substances, posing significant risks to the institution's key research projects.

The ministry also warned of the threat to biological security from invasive species sent through postal channels. National security agencies have discovered that some parcels from overseas have been used to introduce invasive species like red-eared turtles, snapping turtles, American bullfrogs, and red imported fire ants into China. These species, known for their strong reproductive capabilities, can outcompete local species for resources, disrupt ecosystems, and pose serious risks to the country's biodiversity and ecological balance. They may also threaten the safety of people and property.

The Ministry of State Security urged the public to remain vigilant and report any suspicious activities related to state secrets or national security within the delivery sector. Citizens are encouraged to cooperate with authorities in investigations and evidence collection efforts.