Moscow (AP) — Armed militants killed more than 15 police officers and several civilians, including a priest, in Russia's southern Dagestan region on Sunday. Police officers killed four gunmen in Makhachkala and two in Derbent, officials said.

Dagestan Governor Sergei Melyukov said in a video statement early Monday that gunmen opened fire on two Orthodox churches, a synagogue and a police post in two cities. Russia's National Anti-Terrorism Committee said the attacks took place in the predominantly Muslim region with a history of armed extremism. It described the attacks as terrorist acts. Following the incident, the region has declared Monday, Tuesday and Wednesday days of mourning.

The terrorists targeted the church and the police post 

Dagestan's internal affairs minister said a group of armed men attacked a synagogue and a church in the city of Derbent, located near the Caspian Sea. According to state media, both the church and the synagogue caught fire. There have been similar reports of attacks on a church and a traffic police post in Makhachkala, the capital of Dagestan.

Terrorists slit the priest's throat 

According to the report, gunmen slit the throat of priest 'Father Nikolay' in a church in Derbent, while the security guard was shot dead, news agency AP reported, citing the Ministry of Internal Affairs of Dagestan. One of the law enforcement officers killed in the attack was the head of the 'Dagestan Lights' police department. 

Anti-terrorism operation announced in the region

Authorities have announced a counter-terrorism operation in the area. The Anti-Terrorism Committee said that five gunmen have been 'eliminated'. However, it is not yet clear how many terrorists were involved in the attacks. No one has yet claimed responsibility for the attacks. Authorities have launched a criminal investigation into this terrorist act.

Claim of conspiracy from abroad 

Russia's state news agency TASS quoted law enforcement sources as saying that a Dagestan official was detained over the involvement of his sons in the attacks. Melikov claimed without providing any evidence that the attacks were probably planned abroad.