The death toll from a series of brazen attacks on churches and synagogues in Russia's mainly Muslim region of Dagestan rose to 20 after gunmen went on the rampage in coordinated attacks in two of the republic's most important cities.
Gunmen with automatic weapons burst into an Orthodox church and a synagogue in the ancient city of Derbent on Sunday evening, setting fire to an icon at the church and killing a 66-year-old Orthodox priest, Nikolai Kotelnikov.
Attacks in Dagestan raise fears of Islamist threat – an expert's view. – Reuters
In the city of Makhachkala, about 125 km (75 miles) north on the Caspian Sea shore, attackers shot at a traffic police post and attacked a church.
Gun battles erupted around the Assumption Cathedral in Makhachkala and heavy automatic gunfire rang out late into the night. Footage showed residents running for cover as plumes of smoke rose above the city.
Head of Dagestan Sergei Melikov visits Derbent synagogue. – Reuters
There was no immediate claim of responsibility. Russia's investigative committee said 15 policemen and four civilians were killed. According to Dagestan's healthcare ministry, 46 more people were wounded.
At least five attackers were killed.
Sergei Melikov, the head of the Dagestan region, who on Monday visited the synagogue and church that were attacked in Derbent, said:
"This is a day of tragedy for Dagestan and the whole country."
He said that foreign forces had been involved in preparing the attack, but gave no details.
"This is an attempt to cleave apart our unity."
Dagestan announced three days of mourning. Photos of the dead policemen were lined up on the street by red carnations.
Russian President Vladimir Putin, who has long accused the West of trying to stoke separatism in the Caucasus, sent his condolences to those who lost loved ones.
Dagestan is a mainly Muslim republic of Russia's North Caucasus, a patchwork of ethnic groups, languages and regions that live in the shadow of the Caucasus mountains between the Caspian Sea and the Black Sea.
Dagestan
The attack on Christian and Jewish places of worship stoked fears Russia may be facing a renewed militant Islamist threat just three months after a deadly attack in Moscow.
In the Moscow attack, 145 people were killed at the Crocus concert hall, an attack claimed by Islamic State.
In October, after the war in Gaza broke out, rioters waving Palestinian flags broke down glass doors and rampaged through Makhachkala airport to look for Jewish passengers on a flight arriving from Tel Aviv.
United Nations Secretary-General Antonio Guterres condemned the attack and conveyed his condolences, a spokesperson said.
Derbent, one of the oldest continuously inhabited cities on earth, is home to an ancient Jewish community and a UNESCO World Heritage site.
The Crocus concert hall was destroyed during the attack in March which killed 145 people. – Reuters
Russian investigators said it was a "terrorist" attack but did not give details of the attackers.
Russia's state media cited law enforcement as saying two sons of Magomed Omarov, the head of central Dagestan's Sergokala district, were among the attackers in Dagestan. They were killed and their father was detained, state media said.
June 24 to 26 have been declared days of mourning in Dagestan, Melikov said, with flags lowered to half-mast and all entertainment events cancelled.
The Russian empire expanded into the Caucasus in the early 19th century, but an insurgency after the 1991 fall of the Soviet Union led to two wars.
In August 1999, Chechen fighter Shamil Basayev led fighters into Dagestan in a bid to aid Dagestani Wahhabist fundamentalists, triggering a major bombing campaign by the Russian military ahead of the Second Chechen War.
What is known about the attacks in Russia's Dagestan?
The attacks
Just before 6pm local time (1500 GMT) on Sunday, gunmen with automatic weapons attacked an Orthodox church and a synagogue in Derbent, home to an ancient Jewish community and a UNESCO World Heritage site, the interior ministry said.
Russian media carried footage of the synagogue on fire. Izvestia newspaper said two gunmen ran into the Orthodox church, tried to set fire to its main icon and then opened fire.
At the same time, gunmen also attacked a traffic police post in the local capital of Makhachkala, about 125km (75 miles) north of Derbent, the ministry said.
Gun battles ensued between law enforcement agencies and the attackers. There was heavy shooting around the Assumption Cathedral in Makhachkala and reports of gunfire on a beach. Repeated automatic gunfire rang out across both cities.
A counter-terrorism regime that allows authorities greater powers to clamp down on people's movement and communications was declared in the region overnight before being lifted early on Monday.
The victims
Sergei Melikov, the head of the Dagestan region, said more than 15 policemen had been killed as well several civilians, including an Orthodox priest, Nikolai Kotelnikov, who had worked for more than 40 years at the church in Derbent.
Izvestia said he was killed in front of family members. He was the only confirmed casualty of the attacks.
Patriarch Kirill of Moscow, the head of the Russian Orthodox Church, called for resistance to any attempts to radicalise religion.
"I am convinced that it is necessary to do everything possible to exclude the very possibility of attempts to radicalise religious life, to stop any manifestations of extremism and interethnic hostility in any form," Kirill said.
"The present and future of our country largely depends on this," he said.
The attackers
Six attackers were killed, Melikov said.
Russia's state media cited law enforcement as saying that among the slain attackers had been two sons of the head of central Dagestan's Sergokala district, and that the official been detained by investigators. Another of the attackers was his nephew.
There was no immediate claim of responsibility.
"We understand who is behind the organisation of the terrorist attacks and what goal they pursued," Melikov said, adding that foreign forces had been involved in preparing the attack.
"This is an attempt to cleave apart our unity."