Russian media reports say a suicide bomber has blown himself up in the republic of Daghestan, injuring at least 42 people, including several police officers.
The bomber broke through a police cordon in the capital, Makhachkala, where security officers were battling militia fighters.
At least two Islamist rebels were killed in that incident.
On September 24, at least five suspected Islamist terrorists, including a woman, were killed in Daghestan.
Daghestan has been the scene of bloody clashes between forces loyal to Moscow, criminal gangs, and Islamists striving for independence from Russia.
The region is plagued by almost daily violence.
compiled from agency reports