The number of people killed during a suicide bombing in Grozny, the capital of Russia's troubled North Caucasus republic of Chechnya, has risen to five, while at least 12 others were wounded in the blast, Russian news agencies reported.
The attack took place Sunday at the entrance to a concert hall where festivities were planned to celebrate Grozny's city day holiday, which was also Moscow-backed leader Ramzan Kadyrov's birthday.
"Police officers who were manning metal detectors at the entrance of the concert hall noticed a suspicious young man. When the police officers decided to check the individual, the man blew himself up," a local police officer told the state-run RIA Novosti news agency.
There were no reports of civilian deaths or injuries, RIA said.
The site of two separatist wars and a festering Islamic insurgency, Chechnya has seen a period of relative calm under the strong-arm rule of Kadyrov, and suicide bombings have been a rare occurrence in recent years.
The attack was the first major act of violence since the death of insurgent leader Doku Umarov who was killed in a clampdown during Russia's hosting of the Winter Olympics in Sochi, on the western edge of the Caucasus Mountains.
Kadyrov, who became leader of Chechnya in 2007, has vowed to wipe out the militants but has faced criticism from human rights groups for the disappearances of those suspected of being linked to the insurgency and torture. He calls the accusations an attempt to blacken his name.
Kadyrov, who has been threatened personally by the insurgents who call themselves the Caucasus Emirate, said that the suicide bomber had arrived at the concert hall dressed like a policeman.
The bomber was later identified as 19-year-old Opti Mudarov, the Interfax news agency reported, citing an undisclosed source close to the case
The last suicide bombing in Grozny was in 2012 and killed at least four soldiers.
In Kabardino-Balkaria, nearly 200 kilometers (125 miles) west of Chechnya, security officials also killed two militants on Sunday, state television reported.
Material from The Moscow Times was included in this report.
