In this grab taken from a handout footage on June 24, 2024, Dagestan region governor Sergei Melikov visits a burned out synagogue, which was attacked by gunmen, in Derbent.

MOSCOW – Gunmen opened fire at a synagogue, an Orthodox church, and a police post in attacks across two cities in Russia’s North Caucasus region of Dagestan on Sunday, June 23, killing an Orthodox priest and at least 15 police officers, the region’s head said.

“This is a day of tragedy for Dagestan and the whole country,” Sergei Melikov, governor of the Dagestan region, said in a video published early on Monday on the Telegram messaging app.

The simultaneous attacks across the cities of Makhachkala and Derbent came three months after 145 people were killed in an attack claimed by the Islamic State on a concert hall near Moscow, Russia’s worst terrorist attack in years.

There was no immediate claim of responsibility for the attacks in the volatile North Caucasus region.

“We understand who is behind the organization of the terrorist attacks and what goal they pursued,” Melikov said, without disclosing further details.

Russia’s state media cited law enforcement as saying that among the attackers had been two sons of the head of central Dagestan’s Sergokala district, who it said had been detained by investigators.

Melikov said that among the dead, in addition to the police officers, were several civilians, including an Orthodox priest who worked in Derbent for more than 40 years.

Six of the gunmen were shot and killed as the incidents unfolded, Melikov said. Russian state news agencies cited the National Anti-Terrorist Committee as saying that five of the gunmen had been killed.

Reuters could not independently verify the reports on how many people or gunmen were killed in the attacks.

June 24-26 have been declared days of mourning in Dagestan, Melikov said, with flags lowered to half-staff and all entertainment events cancelled.

The restive region was in the 2000s hit by an Islamist insurgency spilling over from neighboring Chechnya, with Russian security forces moving aggressively to combat extremists in the region.