More than 15 police officers have been killed in armed attacks in Russia's Dagestan, the head of the region said early Monday.

Sergey Melikov commented on the attacks in the cities of Makhachkala and Derbent on his Telegram channel.

According to reports, the attackers targeted a police checkpoint in Makhachkala as well as two churches and a synagogue in Derbent. The two cities are located about 128 kilometers (79.5 miles) from each other.

Describing it as a "terrorist attack," Melikov said: "We know who is behind this and what the organizers of these attacks aimed for. War has come to our home."

He noted that Dagestani police have been confronting those responsible for the attacks.

"More than 15 police officers lost their lives in this unprecedented terrorist attack. They were defending peace and order in Dagestan with arms. Among the deceased are several civilians, including a priest."

He also reported that the active phase of counter-terrorism operations in Makhachkala and Derbent has been completed, saying that six gunmen responsible for the attacks were neutralized.

"Efforts will be made to identify all plots orchestrated by external forces and terrorist cells. The situation is under the control of state institutions," he said.

The Russian Investigative Committee classified the attacks as acts of terrorism and announced an investigation into the incidents.

A fire resulting from the attack on the synagogue in Derbent has been extinguished.

The head of the Russian Republic of Ingushetia as well as the governor of the Stavropol territory bordering Dagestan announced that security measures have been strengthened due to the incidents.