At least six police officers and a priest were killed in attacks in two cities in Russia’s southern republic of Dagestan after gunmen opened fire on Sunday at a synagogue, at least two churches and a police post, the local interior ministry said.

A dozen or more police officers were wounded in two seemingly coordinated attacks, Russian state news agencies reported, citing local law enforcement officials. The shootings occurred in Dagestan’s capital, Makhachkala, and Derbent, a city on the border with Azerbaijan.

As of Sunday evening, it was unclear how the total casualty count split across the two cities, but Derbent police officials said that gunmen opened fire at a synagogue and a church, killing at least one police officer and wounding another.

Russian state news agencies posted videos of the Derbent synagogue engulfed in flames. In a statement, the local police said that the synagogue and the church had been “burned down.”

In Makhachkala, a sprawling city on the Caspian Sea, gunmen opened fire on a street that is also home to a local synagogue. According to videos posted by Dagestan’s Ministry of Interior, gunmen were on the loose in the city, opening fire and forcing people out of their cars.

The Russian Investigative Committee, the country’s equivalent to the F.B.I. said it had opened a terrorism investigation into the attacks.

Dagestan is a predominantly Muslim republic that is also home to a Jewish population, and has experienced a heightened level of violence for at least three decades. But ethnic and religious tensions in the republic have worsened since the war between Israel and Hamas in the Gaza Strip broke out in October.

In October, an angry mob stormed an airport in Makhachkala searching for Jewish passengers on a flight from Israel. The attack shocked Jews in Russia and drew condemnation from the Israeli government.

Sergei Melikov, the head of Dagestan, said in a statement that Sunday’s attacks appeared aimed “destabilizing the public situation.”

At least four of the gunmen were killed by law enforcement officers, the local police said. With some of the gunmen still at large, the police said they had blocked entrances to Makhachkala.

Neither the number of attackers nor their identities were immediately disclosed.

The shootings came only months after four terrorists attacked a major concert hall on the outskirts of Moscow, killing 145 people in a shooting rampage and fire. The Islamic State claimed responsibility for the attack; American officials have attributed it to ISIS-K, a branch of the group.