At least five people were killed and four others wounded when a gunman opened fire with a hunting rifle on people leaving a Sunday service at a Russian Orthodox church in the Dagestan city of Kizlyar.
Authorities said the gunman was a local resident, and his wife has been detained for questioning. But police have not commented on the possible motive for the attack.
A statement from the Islamic State group, posted on an IS-affiliated militant website on Monday, claimed responsibility for the shooting, saying a Muslim fighter attacked "a Christian temple" in Kizlyar.
The authenticity of the statement could not be confirmed, but the website is regularly used by IS for posting militant statements.
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