MOSCOW (Reuters) - A suicide bomber killed at least five police officers and wounded 12 others on Sunday during festivities for a local holiday in Grozny, the capital of Russia’s troubled North Caucasus region of Chechnya, Russian news agencies reported.

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 reports of civilian deaths or injuries, RIA said.

Following the Chechen separatist wars in 1994-96 and 1999-2000, the insurgency spread across the predominantly Muslim North Caucasus, fueled by an explosive mixture of religion, and anger over corruption and alleged rights abuses

The attack is 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 attacker was a 19-year old from Grozny who disappeared from home two months ago, agencies reported police as saying.

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 TV said.