China's official military newspaper has warned soldiers to ignore internet rumours and maintain absolute loyalty to the party.
This follows the arrest of six people and closure of 16 websites last week, after rumours of a coup spread online.
A leftwing website that expressed support for dismissed political leader Bo Xilai has also been shut.
The moves are believe to be linked to China's leadership change later this year.
The front page commentary in the Liberation Army Daily called on the army to "pay great attention to the impacts of the internet and mobile phones on the mind and thoughts of soldiers", and to manage internet systems in the barracks.
It stressed "the party's absolute leadership over the army", telling troops to "resist all kinds of erroneous ideological invasion, noise disturbance... and not [be] moved by undercurrents".
The commentary did not mention the internet rumours of a coup last week.
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The struggle in the ideological front will be more intense and complicated”
Liberation Army Daily
China will face a once-in-a-decade leadership reshuffle later this year.
However, the sacking of Bo Xilai, the former party chief of Chongqing who was tipped for promotion, has revealed political divisions behind the scenes.
Mr Bo was dismissed following allegations that his police chief and former ally had tried to seek asylum at a US consulate.
Referring to the upcoming 18th party congress, and 85th anniversary of China's People's Liberation Army, the article said: "History taught us that whenever the party and country face a big event, the struggle in the ideological front will be more intense and complicated."
The leftist website Utopia, which has supported Mr Bo, has also been ordered to shut for a month.
The founder and manager of the Beijing-based Maoist site said officials had accused them of posting essays containing malicious attacks and wild comment about the Communist party congress later this year.