MOSCOW — Russia's southern region of Dagestan held the first of three days of mourning Monday following an attack by Islamic militants who authorities say killed 20 people, mostly police, and attacked Christian and Jewish houses of worship in assaults in two cities.
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. It was also the deadliest in Russia since March, when gunmen opened fire at a concert in suburban Moscow, killing 145 people.
An affiliate of the Islamic State group in Afghanistan had claimed responsibility for March's raid and quickly praised the attack in Dagestan, saying it was conducted by ''brothers in the Caucasus who showed that they are still strong."
The Washington-based Institute for the Study of War argued that the Islamic State group's North Caucasus branch, Vilayat Kavkaz, likely was behind the attack, describing it as ''complex and coordinated.''
Dagestan Gov. Sergei Melikov blamed members of Islamic ''sleeper cells'' directed from abroad, but didn't give any other details. He said in a video statement that the assailants aimed at ''sowing panic and fear,'' and attempted to link the attack to Moscow's military action in Ukraine — but also provided no evidence.
President Vladimir 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.
Kremlin spokesman Dmitry Peskov said Putin has received reports on Sunday's attacks and efforts to help the victims.
The Investigative Committee, the country's top state criminal investigation agency, said all five attackers were killed. Of the 20 people killed, at least 15 were police.