Four police officers have been killed and four others injured in a suicide attack in the Chechen capital, Grozny.
The attack took place outside a hall where a concert marking Grozny's City Day was about to take place.
A statement from the interior ministry said police were searching a "suspicious" young man when he detonated a device.
Grozny was ravaged by two wars between Russia and Chechen separatists but has been relatively calm in recent years.
"Police officers on duty at the event noticed a suspicious young man near metal detectors set up at the concert hall," the ministry's statement said.
"When the police decided to search him and establish his identity, the man blew himself up."
There has been no information about any civilian casualties.
After the collapse of the Soviet Union in 1991, Chechnya saw a brief period of de facto independence, two wars with Russia and an Islamist insurgency.
Moscow-backed leader Ramzan Kadyrov has cracked down hard on militants in recent years and overseen a major rebuilding programme in Grozny.
But sporadic violence continues, however, including a triple suicide bombing in 2011 which killed six people.
http://www.bbc.com/news/world-europe-29498909
