The warning came after a newspaper in the southern city of Volgograd published a cartoon of religious figures to illustrate an article on fighting nationalism and xenophobia.
The local branch of the Kremlin-backed Unified Russia party accused "Gorodskie vesti" of inciting religious hatred and called for a boycott of the daily. The newspaper denies the accusations.
Local prosecutors said they are looking into the publication to see whether there are grounds for opening a criminal investigation.
The "Gorodskie vesti" cartoon shows Jesus, Moses, Buddha, and the Prophet Muhammad watching on television two groups of people about to start a fight. The caption reads: "We did not teach you that." The cartoon illustrates an article titled "Racists Have No Place In Government."
(Interfax, RIA Novosti)