Dagestan, in Russia, has begun three days of mourning after gunmen killed multiple police officers, an Orthodox priest and several others in attacks on synagogues and churches on Sunday across two cities in the North Caucasus region.
"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.
It was not clear how many people died in total in the simultaneous attacks across the cities of Makhachkala and Derbent.
Melikov said more than 15 police officers "fell victim" to what he said was a "terrorist attack"," but he did not specify how many of the police were killed and how many were injured. Russia's Interfax agency reported at least 15 police officers were killed.
The attacks came three months after 145 people were killed in an attack on a concert hall near Moscow, Russia's worst such 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 organisation of the terrorist attacks and what goal they pursued," Melikov said, without disclosing further details. The search for the gunmen will continue until all of them are identified, he added.
Russia's state media cited law enforcement as saying two sons of the head of central Dagestan's Sergokala district were among the attackers and had been detained by investigators.
Melikov said several civilians were among the dead, including an Orthodox priest who worked in Derbent for more than 40 years. The priest, Nikolai Kotelnikov, was "brutally murdered", a spokesman for the Russian Orthodox Church said on Telegram.
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 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-mast and all entertainment events cancelled.