The death toll in an attack by Islamic militants in the Dagestan region of southern Russia has risen to 21 after an injured police officer died in hospital, officials said on Tuesday.

The 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 on Sunday.

It was the deadliest attack 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 carried out 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 on Tuesday that a police sergeant died of his wounds in hospital, taking the total number of victims to 21, 16 of them police officers.

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

Among the dead was the Rev Nikolai Kotelnikov, a 66-year-old Russian Orthodox priest at a church in Derbent. The attack came as the Orthodox faithful celebrated Pentecost, also known as Trinity Sunday.

In the early 2000s, Dagestan saw near-daily attacks on police and other authorities which 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 on to the tarmac, chased passengers and threw stones at police.