An incomplete list of everything threatening China's national security

What do snapping turtles, tissue boxes and college students looking for part-time jobs have in common?

They all might be hiding threats to China's national security.

That, at least, is the message being pushed by the Ministry of State Security, China's main intelligence agency, in a flurry of recent social media posts. Every few days in the past month, the agency has published an addition to its long, wide-ranging list of dangers, with the stated goal being to keep the public vigilant and enlist it to fend off foreign enemies.

The drumbeat is part of a broader push by China's top leader, Xi Jinping, to make national security the country's top priority, above other long-standing goals, such as economic development.

In Beijing's view, that requires far more than strengthening spy agencies or investing in the military. It requires activating every Chinese citizen to be on the lookout, in what China has called a "whole of society" mobilisation.

The creation of the usually secretive security ministry's social media account last year was one step toward that goal. The account's posts are reaching a wide audience: Each one on WeChat has been read more than 100,000 times -- the maximum view count that the messaging platform will show -- and hashtags about the warnings have been top trending topics on Weibo, another social media site.

In the past several weeks, here are some of the risks the security agency has warned about:

Apparent Good Samaritans: One recent post titled "Beware! Wolves in Sheep's Clothing" warned readers that spies might pose as generous donors. It told the story of a young orphan with top grades, who one day was approached by a stranger offering to financially support him through college. Over the years, the stranger kept in touch with the student and encouraged him to apply for a government job. When he landed it, the stranger asked him to share confidential information about China's economic policies. Fortunately, the post said, the student recalled the "anti-espionage propaganda education he'd received" and reported the stranger, whom the Chinese authorities confirmed was a foreign spy.

Courier services: Another post was called "These types of packages are not allowed!" Besides reminding people not to mail top-secret documents to spies, it warned that "some foreign organisations and individuals" had shipped animals, such as alligator snapping turtles, American bullfrogs and red fire ants, to China to reproduce as invasive species and destroy local ecosystems.

Students looking for cash: College students are a persistent source of worry for Beijing. Another post warned that students looking for part-time work may be targets for spies who ask them to take photos of scientific research sites for pay.

Students applying to colleges abroad: But students don't need to be sharing sensitive information to threaten national security. They may also be unwitting vessels for spreading a negative image of China -- as described in another post, where a study-abroad agency purportedly inserted political content critical of China into a student's application materials, to help them win admission overseas. "Without knowing it," the post said, the student went from "a young student with a simple resume to an anti-China vanguard."

Pretty much anything: Pens can contain hidden cameras. Lighters can be bugged with listening devices. That dragonfly? Actually a tiny aerial drone. And beware the tissue box, which a guest may bring to a dinner party where major infrastructure projects are being discussed. A recorder may be hidden inside. "Some unassuming daily objects may contain mysteries," the post said, above a hotline for reporting spies.

Beijing is certainly not alone in calling for heightened vigilance as relations between China and the West have deteriorated. The United States has also warned, for example, that China is using LinkedIn to recruit spies. Chinese students and scholars have also complained of being detained or denied entry at the United States border even with valid visas.

China's desire to put these scenarios at the top of people's minds, and make suspicion a part of everyday life, is what sets it apart, said Andrew Chubb, a scholar of Chinese politics at Lancaster University in England.

"The question is the extent to which you want everybody thinking about that. Because it has major downsides in terms of constraining the activities people will engage in, interfering in people-to-people contact, just making people stop what they otherwise productively would be doing," Chubb said.

It is unclear how well the campaign is working. China's internet is heavily censored, and many comments online are supportive. Even so, some sarcastic comments have seeped through, asking, for example, whether mailing newspapers could entail leaking national secrets.

The fact that Beijing is pushing out these posts at all suggests that it knows many Chinese do not see the same threats that it does.

"Right from the top, it was perceived that the level of paranoia, if you like, was insufficient among the general population," Chubb said. "So there was a desire, and a continuous desire since then, to elevate it."