Addressing those born from 1990 who are "becoming the core of the army", the People's Liberation Army (PLA) Navy said in a social media post that young soldiers should avoid revealing their military identity online as they could be "extremely easy" targets of criminals.
The political and confidential nature of the military profession dictates that the military personnel identity must not be exposed online, it said.
"Distinguish carefully and keep some distance when making friends online," a line in the post advised, and "never lose sight of your principles and make random friends with netizens".
The navy also cautioned against virtual gambling, which is illegal in China, likening gambling addiction to being "possessed by a demon" and warning against schemes that could lead to a "fall into an endless abyss" of debt.
China's military projects an image of power, from launching drills around democratically governed Taiwan to deploying patrols in the South China Sea. But President Xi Jinping, also the military's commander-in-chief, has often warned that the armed forces face "deep-seated" problems from within, including corruption and a lack of discipline.
Young soldiers are not the only demographic singled out. Xi has also stressed political loyalty from senior military personnel.
At a military conference in June, Xi emphasised upholding the Chinese Communist Party's "absolute leadership" over the PLA and that the armed forces must always "uphold their core values, maintain purity, and strictly adhere to discipline".
Xi attributed the root cause of problems to the lack of ideals and beliefs, calling on the armed forces particularly senior cadres, to "introspect, engage in soul-searching reflections, and make earnest rectifications", according to official news agency Xinhua.
