In a video released early on Monday, Sergei Melikov, the governor of Dagestan, said that armed militants killed more than 15 police officers, several civilians and an Orthodox priest in Dagestan, a republic in southern Russia.

According to authorities, the gunmen shot at two Orthodox churches in two cities as well as a synagogue, and a police station.

The National Anti-Terrorist Committee of Russia described the attacks as terrorist acts in a predominantly Muslim area with a long history of armed rebellion.

In the region, Monday, Tuesday, and Wednesday have been declared days of mourning.

Dagestan’s Interior Ministry reported that a group armed with guns shot at a Synagogue and Church in Derbent on the Caspian Sea. According to the state media, both the synagogue and the church caught fire. Fast simultaneously, news reports emerged about a fire at a church in Makhachkala, the capital of Dagestan.

Authorities in the area announced a counterterrorism operation. The Anti-Terrorist Committee claimed that five “gunmen” were “eliminated,” while the governor stated that six “bandits”, had been “liquidated.” These numbers could not be reconciled immediately, and it was unclear how many militants participated in the attacks.

No one immediately claimed responsibility for the attack. Authorities launched a criminal probe on the terrorist charge.

Russian state-run news agency Tass quoted law enforcement sources stating that a Dagestani government official was arrested over the involvement of his sons in the attacks.

Melikov stated in a video statement that law enforcement agencies and local authorities were in control of the situation. He also promised that investigations into the attacks would continue until all “sleeping cells” of militants have been uncovered.

He said, without giving any evidence, that the attack could have been planned from abroad. He also referred to what the Kremlin refers to as “the special operation” in Ukraine, in an attempt to appear to link it to the attacks.

Gunmen opened fire in March on a crowd of people at a concert venue in a suburb of Moscow, killing 145. The Islamic State claimed responsibility, but Russian officials tried to connect Ukraine with the attack. They did not provide any proof. Kyiv has categorically denied any involvement.