Three people were killed and two dozen injured at Moscow's largest cemetery on Saturday in a brawl between ethnic groups, and witnesses said the battle was for control over the lucrative businesses of providing burial services.
Some of the 200 or so people involved used weapons, including guns, police and witnesses said. More than 90 people were detained after riot police broke up the fight at the Khovanskoye cemetery in southwest Moscow.
With Russia's economy battered by Western sanctions and low prices for its oil exports, migrants struggle to find work and ethnic criminal groups add to social tensions.
The Moscow city health department reported three people had been killed and 23 hospitalized, including four gravely hurt.
In amateur video taken from a passing car and shown on Rossiya 24 TV channel, a passenger can be heard screaming: "It's like a war zone!"
Pictures posted on social networks showed young men holding iron rods, spade shafts and baseball bats as they rushed into the fighting.
Reuters witnesses saw a young man lying dead on the pavement near an overturned car, while a forensic expert bent over him. About 10 mainly young men lay handcuffed on the asphalt while police with Kalashnikov rifles looked on.
RIA news agency quoted a cemetery official as saying people from Russia's North Caucasus regions of Chechnya and Dagestan had attacked migrants from ex-Soviet Uzbekistan and Tajikistan working there, attempting to take over their jobs.
Quoting a police source, TASS news agency said ethnic Chechens, Dagestanis, Uzbeks and Tajiks were among those detained.