Gunmen fired on a synagogue and a church in Derbent and a police station in Makhachkala.
The Interior Ministry of the Russian republic of Dagestan said gunmen killed at least six police officers in what appeared to be a coordinated attack targeting a synagogue, an Orthodox church and a police station.
Twelve people were wounded in the attacks in the cities of Derbent and Makhachkala on Sunday evening.
Both the synagogue and the church are in Derbent, home to a long-established Jewish community in the Muslim-majority region of the North Caucasus, from where the police station attack took place in Makhachkala, the capital of the republic of Dagestan, about 125 kilometers (78 miles) away.
Local authorities told Reuters that a synagogue in Derbent was set on fire as a result of the attack, and witnesses reported seeing smoke coming from the church.
Two of the attackers were shot dead, Russian media reported, citing the Interior Ministry.
The Derbent attackers had earlier been seen fleeing in a car.
“Tonight in Derbent and Makhachkala unidentified individuals tried to destabilize the public situation,” said Sergey Melikov, head of the Republic of Dagestan. “Dagestani police stood before them. According to preliminary information, there are casualties among them. All agencies are acting in accordance with instructions… The identity of the attackers is being determined.”
Al Jazeera reporter Daniel Hawkins from Moscow said there were also reports that a priest from the church had been killed.
Hawkins noted that Dagestan experienced separatist violence in the 1990s and early 2000s.
“Over the years, the violence there has subsided,” Hawkins said, explaining that the region has never seen the kind of conflict that has engulfed Russia’s neighboring republic of Chechnya, which has seen two brutal wars between Russian forces and separatists during the same period.
“A coordinated attack of this kind targeting a private religious institution is highly unusual and will undoubtedly shock people across Russia,” Hawkins said.