One of the posters, shown on the newspaper`s website, had pictures of three people with names that appeared to be Uighur, a mainly Muslim minority group that calls Xinjiang home.
The four had all been arrested, the newspaper reported, citing Shanxi police.
Calls to police in Shanxi seeking comment went unanswered.
It is not clear why Shanxi would have been the target of attacks. The majority of violent incidents blamed by China on Islamist militants happen in Xinjiang itself.
Hundreds of people have been killed in violence in Xinjiang in the past few years. The government blames the unrest on Islamist militants who want to establish an independent state called East Turkestan.
Many Uighurs chafe at pressure to take on Chinese customs and language, which has often been coupled with curbs on their religious and cultural practices. China denies having any repressive policies.
Exiles and many rights groups say the real cause of the unrest is heavy-handed Chinese policies, including curbs on Uighur culture, and a dearth of economic opportunity.
China says Uighurs have gone to Syria and Iraq to fight with militant groups there.
Last month, the Islamic State group said it had killed a Chinese captive, prompting outrage in Beijing.
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