Two women suicide bombers killed 16 other people when they blew themselves apart at an open-air rock festival staged at a Moscow airfield today, Russia's interior minister said.
Mr Boris Gryzlov blamed Chechens opposed to President Vladimir Putin's plan, announced a day earlier, to hold a Kremlin-run local presidential election in Chechnya in October.
The minister told reporters at the scene that 20 people were injured.
If it was carried out by Chechens, the suicide attack would be a new instance of a tactic used by the region's Muslim militants, including several women, only relatively recently in their decade-old campaign to break from Moscow's control.
The women had apparently been prevented from entering the site proper and blew themselves up outside admission booths at Tushino airfield, where thousands had gathered for the all-day event featuring numerous well-known Russian rock bands.
"Two explosions occurred. These were two women suicide bombers. As a result, 16 people have died. This does not include the suicide bombers. Twenty people have been taken to hospitals with injuries," said Mr Gryzlov.
Yesterday, Mr Putin had issued a decree ordering a local presidential election to be held in Chechnya on October 5. "I presume that this inhumane situation, this terrorist act, is linked with the staging of this event," Mr Gryzlov said. "If the explosions had occurred on the field itself, the consequences would have been far more serious."
One body lay sprawled out by an admission booth outside the concert venue in Moscow's northern suburbs. A second lay on the roadside nearby.
Mr Gryzlov said the concert would gradually be wound down, with spectators evacuated in orderly fashion. There was no claim of responsibility, but Chechen separatists have in the past employed suicide bombers and have attacked Moscow events, including a theatre show last year.
Media reported Moscow hospitals preparing beds for an influx of injured.
Mr Putin's decree yesterday was a key part of a Kremlin plan for a political solution to the crisis. He secured support for a new regional constitution in a referendum held in March.
Guerrillas, who continue to operate in the partly mountainous region despite the presence of thousands of troops, have rejected the Kremlin plan and vowed to press on with their campaign to oust the military.
But many rebels reject the use of suicide bombers.