MOSCOW (AP) — The death toll in the attack by Islamic militants in Russia’s southern region of Dagestan has risen to 21 after a wounded police officer has died in a hospital, officials said Tuesday.

Sunday’s attack, in which militants attacked Christian and Jewish houses of worship and fired at police in the cities of Derbent and Makhachkala in the predominantly Muslim region in the North Caucasus, was 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, which claimed responsibility for March’s raid, was quick to praise the attack in Dagestan, saying it was conducted by “brothers in the Caucasus who showed that they are still strong.”

The Investigative Committee, Russia’s top state criminal investigation agency, said all five attackers were killed.

Mavsum Ragimov, head of the Derbent region, said Tuesday that a police sergeant died of his wounds in a hospital, bringing the total number of victims to 21, 16 of them police.

Medical authorities in Dagestan said Monday at least 46 people were injured, 13 of them police.