Suicide bomber kills four police in Russia's Chechnya - agencies
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 Moscow-backed leader Ramzan Kadyrov, and suicide bombings have been a rare occurrence in recent years.
The attack took place at the entrance to a concert hall where festivities were planned to celebrate Grozny's city day holiday, which is also 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 RIA news agency.
There were no immediate reports of civilian deaths or injuries, RIA said.
(Reporting by Thomas Grove; Editing by Kevin Liffey)