At least 20 people were killed, including civilians and police officers, when gunmen opened fire at two Orthodox churches, two synagogues, and a police station in separate attacks in the cities of Derbent and Makhachkala in Russia's North Caucasus region of Daghestan.
Investigators earlier said that four civilians were killed, with 15 police officers reportedly killed in the June 23 attacks.
At least 46 people were injured, according to Russian officials.
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Shock And Devastation After Attacks In Russia's Daghestan Region
Regional Governor Sergei Melikov, in a video statement posted on Telegram early on June 24, said that among the civilians killed was 66-year-old Father Nikolai, who served for more than 40 years in the Orthodox church in Derbent.
Melikov said that six "bandits" were "liquidated" by security forces.
Russia’s National Anti-Terrorism Committee declared the security operation over by the morning of June 24.
Among those detained was Magomed Omarov, the head of the central Sergokala district and secretary of the local branch of the United Russia party, whose home was searched. Omarov was expelled from the party for actions discrediting the organization, United Russia's press service in Daghestan said.
Three of the attackers who were killed have been identified, according to Interfax, which quoted an unidentified source as saying two of Omarov's sons and one of his nephews were among the slain attackers.
The attacks came just three months after 145 people died and hundreds were injured when Islamic State (IS) extremists opened fire in a crowded concert hall on the outskirts of Moscow, Russia's worst terrorist attack in years.
There was no immediate claim of responsibility by IS or any other groups for the attacks in the volatile North Caucasus region on June 23.
SEE ALSO: Tajik Foreign Minister Speaks Out About Treatment Of Crocus City Hall Suspects"This is a day of tragedy for Daghestan and the whole country," Melikov said after officials announced three days of mourning for the region.
According to a local religious organization in the majority Muslim region, the attacks occurred on a religious holiday in the Russian Orthodox Church.
"The radicals want to pit us against each other with all their might and burn interfaith bridges. But they won't succeed," the organization said.
The chairman of the public council of Russia's Federation of Jewish Communities, Boruch Gorin, said on Telegram that synagogues in both cities caught fire during the attacks.
"Two are killed: a policeman and a security guard," Gorin said.
The Israeli Foreign Ministry said the synagogue in Derbent was burned to the ground and shots had been fired at a second synagogue in Makhachkala.
Derbent is home to an ancient Jewish community and is a UNESCO World Heritage site.
The attack on the police station occurred in Makhachkala, the capital of Daghestan, 125 kilometers north of Derbent.
Unknown assailants attacked a traffic police post, and according to the Interior Ministry of Daghestan, two assailants were killed in Makhachkala, whose airport in October was shut down for several days when a mob shouting anti-Jewish epithets stormed it after the arrival of a flight from Israel.
Anti-Jewish protests broke out in several cities in the region after the October 7 attack on Israel by Hamas, which has been designated a terrorist organization by the United States and the European Union.
Months later, after the deadly March 22 massacre at the Crocus City Hall concert venue near Moscow, Russia's Federal Security Service (FSB) detained four people in Daghestan suspected of providing financing and weapons to participants.
Responsibility for that attack was claimed by an offshoot of IS known as Islamic State-Khorasan. Russian investigators said the assault was carried out by four men, all Tajik nationals.
Russian authorities arrested 11 Tajik citizens and a Kyrgyzstan-born Russian citizen in connection with the attack, Russia's worst terrorist attack in two decades.