- Eight were killed on the spot and four died in hospital after the explosion
Russia lost a dozen elite Marines when they cooked food on an open fire and caused an explosion with live ammunition nearby.
Eight others were injured in the incident that Vladimir Putin's regime tried to cover up.
According to reports, an RPG-7 grenade launcher caught fire and exploded at the Kuzminsky military training ground in the Rostov region bordering Ukraine.
Eight Marines from the 155th Separate Guards Marine Brigade, based in Vladivostok, were killed on the spot.
Four others died in hospital, according to Rostov's News 166 channel, which said the humiliating tragedy had been confirmed by three independent sources.
“About twenty people from (the Marine Brigade) lit a fire next to ammunition supplies during their lunch break. An RPG-7 grenade launcher rolled into the fire and exploded,” 161.ru quoted a government source as saying.
An explosion at the Kuzminsky training ground in the Rostov region, where twelve elite Russian marines were killed and eight injured as they cooked on a fire that set a nearby ammunition depot ablaze
It was believed that the troops would be deployed in Putin's illegal war in Ukraine.
All the dead are said to have been marines from the Primorye region of Russia.
Marines from the Primorye region of Russia.
The dead and injured from the lunch meal have not been mentioned.
A major criminal case has been initiated due to a suspected violation of safety regulations.
Pacific Fleet Commander Admiral Viktor Liina, 55, visited the training base to lecture the rioter about the blunder, it was reported.
Neither the Russian Defense Ministry nor the Investigative Committee have commented on the fiasco.
A soldier who witnessed the horror revealed details, but it has taken since the November 3 event for the details to be verified.
MailOnline was unable to verify the details of the Russian reports.
In February, Russian soldiers in Kursk, which also borders Ukraine, were reported killed in an explosion caused by the men using a stove.
The soldiers poured gasoline on an open fire and caused an explosion, Russian Telegram channel Baza reported.
Russian elite troops of the 155th Separate Guards Marine Brigade, located in Vladivostok
In January, a Russian sergeant killed three people and injured 16 after accidentally detonating a grenade in his student house near an ammunition dump, which also caused a large explosion.
A local emergency services source said: 'The preliminary cause of the explosion is careless handling of ammunition.'
Emergency services told Interfax that a sergeant inadvertently detonated an RGD-5 anti-personnel grenade in the building's sleeping quarters, next to the weapons storage room, causing an explosion and fire that grew to 450 square meters.