At least 15 police officers and a priest were killed by gunmen on Sunday in what appear to be coordinated attacks on multiple places of worship in Russia’s southernmost Dagestan province, local authorities said.

Sergey Melikov, head of the Dagestan Republic, said at least six “militants” were also killed following the attacks on churches, synagogues and police posts in the cities of Derbent and the regional capital Makhachkala, which are about 120 kilometers (75 miles) apart.

A priest killed during an attack on a church in Derbent was identified by Dagestan Public Monitoring Commission Chairman Shamil Khadulaev as Father Nikolay. “They slit his throat. He was 66 years old and very ill,” Khadulaev said.

A security guard armed with a pistol was also shot, Khadulaev said. The guard’s condition, along with the total number of victims, remains unclear.

No group has yet claimed responsibility for the attacks, which come three months after ISIS affiliate ISIS-K claimed an assault at the Crocus City Hall in Moscow that claimed more than 140 lives in one of Russia’s deadliest terrorist atrocities in years.

Law enforcement agencies told state-run news agency TASS that the gunmen in Dagestan were “adherents of an international terrorist organization.”

Dagestan is a predominantly Muslim region home to a small Christian and even smaller Jewish minority. Russian security forces fought an Islamist insurgency in the mountainous region in the 2000s that spilled over from neighboring Chechnya, though attacks have become rarer in recent years.

The Muftiyat of the Republic of Dagestan, a centralized Islamic organization that previously reported on the casualties, has since deleted all posts associated with its count of those dead and wounded.

Earlier, local authorities reported that at least nine people had been killed and 25 injured in the attacks.

The Muftiyat now says “law enforcement officers, clergy, and ordinary citizens” are among the victims but does not provide specific numbers.

One of the law enforcement officers killed was Mavludin Khidirnabiev, the head of the “Dagestan Lights” police department, according to the Dagestan Ministry of Internal Affairs’ Telegram channel.

Nighttime video, shared by the Republic of Dagestan’s Ministry of Internal Affairs, showed at least a dozen law enforcement officers — who appear to be armed and wearing tactical gear — outside the gates of a cathedral in northwestern Makhachkala. CNN has geolocated the video to the gates of Svyato-Uspenskiy Sobor, a Russian Orthodox cathedral in Makhachkala.

Earlier Sunday, TASS reported that a security guard was killed in a shootout at Svyato-Uspenskiy Sobor, and 19 people had locked themselves inside the premises during the attack. While it is unclear if the standoff has fully ended, those who had holed up there have since been evacuated to safety, TASS reported, citing the Ministry of Internal Affairs of Dagestan.

Meanwhile, two synagogues in Dagestan — one in Derbent and one in Makhachkala — were attacked, according to a statement from the Russian Jewish Congress (RJC).

The attack on the synagogue in Derbent happened 40 minutes after evening prayer, according to the RJC. Attackers “set the building on fire using Molotov cocktails,” while police and security guards were killed outside, it said.

Photos showed large flames and plumes of smoke billowing heavily out of a series of windows on at least one floor of the structure.

“The exact number of dead and wounded is being clarified,” the RJC said. The organization added that it will “take part in the restoration of synagogues and provide assistance to the families of the victims.”

The Israeli Foreign Ministry said the Derbent synagogue had “burned to the ground” and that local guards had been killed, while the synagogue in Makhachkala had been attacked by gunfire.

“As far as is known, there were no worshipers in the synagogues at the time of the attack, and there are no known casualties from the Jewish community,” the ministry said in a statement.

Security guards had been placed outside of local synagogues ever since an antisemitic mob stormed through the local airport in October.

An attack was also reported at a police traffic post in Makhachkala.

In an earlier Telegram post, Melikov, the head of Dagestan, said, “unknown persons made attempts to destabilize the social situation. Dagestan police officers stood in their way. According to preliminary information, there are victims among them.”

Melikov said the identities of the attackers was being established, an operational headquarters had been set up and a counter-operation was underway.

He urged the public to remain calm. “Panic and fear are what they were counting on,” he said. “They won’t get this from Dagestanis!”

The Investigative Directorate of the Investigative Committee of Russia for the Republic of Dagestan said it had launched a terror investigation into the attacks under the Criminal Code of the Russian Federation.

“All the circumstances of the incident and the persons involved in the terrorist attacks are being established, and their actions will be given a legal assessment,” the agency said in a statement.