A Russian official pointed to Islamic ‘sleeper cells’ after gunmen carried out coordinated attacks on synagogues and churches in two cities in the southern region of Dagestan, killing at least 20 people Sunday. 

Sunday’s violence in Dagestan’s regional capital of Makhachkala and nearby Derbent was the latest that officials blamed on Islamic extremists in the predominantly Muslim region in the North Caucasus, as well as the deadliest in Russia since March, when gunmen opened fire at a concert in suburban Moscow, killing 145 people. The affiliate of the Islamic State group in Afghanistan that claimed responsibility for March’s raid at the Crocus City concert hall quickly praised the attack in Dagestan, saying it was conducted by ‘brothers in the Caucasus who showed that they are still strong.’

Dagestan Gov. Sergei Melikov, selected by Russian President Vladimir Putin to lead the region, blamed members of Islamic ‘sleeper cells’ directed from abroad, but did not give any other details. He said in a video statement that the assailants’ goal was ‘sowing panic and fear,’ and attempted to link the attack to Moscow’s military action in Ukraine – but also provided no evidence.

Putin had sought to blame the March attack on Ukraine, again without evidence and despite the claim of responsibility by the Islamic State affiliate. Kyiv has vehemently denied any involvement.

Of the 20 killed in the armed attacks in Derbent and Makhachkala on Sunday, at least 15 were police, according to the latest figures from Russian authorities on Monday. 

Medical authorities in Dagestan said at least 46 people were injured. Of those, at least 13 were police, with four officers hospitalized in grave condition.

Among the dead was Rev. Nikolai Kotelnikov, a 66-year-old Russian Orthodox priest at a church in Derbent. The attackers slit his throat before setting fire to the church, according to Shamil Khadulayev, deputy head of a local public oversight body. The attack came as the Orthodox faithful celebrated Pentecost, also known as Trinity Sunday.

The Kele-Numaz synagogue in Derbent was also set ablaze.

Shortly after the attacks in Derbent, militants fired at a police post in Makhachkala and attacked a Russian Orthodox church and a synagogue there before being hunted down and killed by special forces, The Associated Press reported. The Investigative Committee, the country’s top state criminal investigation agency, opened a terrorism investigation and said all five attackers were killed.

FBI Director Christopher Wray warned earlier this month of a heightened terror threat following the Biden administration’s withdrawal from Afghanistan, coupled with the Oct. 7 attack on southern Israel by Hamas terrorists, warning of ‘the potential for a coordinated attack here in the homeland, not unlike the ISIS-K attack we saw at the Russian concert hall back in March.’ 

Appearing on CBS’s ‘Face the Nation’ on Sunday, former CIA Deputy Director Mike Morell, who warned in a recent op-ed about the terror threat posed by vulnerabilities at the U.S.-Mexico border, did not address the attacks in Russia specifically but said the Biden administration and Congress ‘lack a sense of urgency’ in responding to intelligence gaps stifling efforts to properly vet illegal immigrants. 

‘There needs to be a sense of urgency about this,’ Morell said. ‘And I think the American public needs to understand what the threat is. That’s why we called for a public congressional hearing just on the terrorist threats to the homeland. Right, not a hearing on threats broadly, but threats to the homeland. And then we need to hear what the administration is doing about this in a broad sense, right. Not the details, but in a broad sense.’

The Washington-based Institute for the Study of War argued that the Islamic State group’s North Caucasus branch, Vilayat Kavkaz, likely was behind Sunday’s attack, describing it as ‘complex and coordinated.’

Russian news reports said the attackers included the two sons and a nephew of Magomed Omarov, the head of the Dagestan regional branch of the pro-Kremlin United Russia party. Omarov was detained by police for interrogation, and United Russia quickly dismissed him from its ranks. Melikov later said Omarov had been removed from his post, Russian state news agencies reported.

In the early 2000s, Dagestan saw near-daily attacks on police and other authorities that were blamed on militant extremists. After the emergence of the Islamic State group, many residents of the region joined it in Syria and Iraq. The violence in Dagestan has abated in recent years, but in a sign that extremist sentiments still run high in the region, mobs rioted at an airport there in October, targeting a flight from Israel. More than 20 people were hurt – none of them Israelis – when hundreds of men, some carrying banners with antisemitic slogans, rushed onto the tarmac, chased passengers and threw stones at police.

After March’s Moscow concert hall attack, Russia’s top security agency reported that it had broken up what it called a ‘terrorist cell’ in southern Russia and arrested four of its members who had provided weapons and cash to suspected attackers in Moscow.

The Associated Press contributed to this report.