At least 11 people were killed and 15 more wounded at a military training ground in the Belgorod region in south-western Russia on Saturday when two volunteers opened fire on other troops, the Russian defence ministry has said.
The ministry said in a statement that the two shooters were nationals from a former Soviet republic and had been shot dead after the attack.
The ministry called the incident a terrorist attack.
According to Baza, a Russian news site with close ties to the police, the shooting took place at 10am local time during shooting practice.
The incident also comes as tens of thousands of newly drafted Russian men are sent to Ukraine, in what has become a highly unpopular move ordered by the Russian president, Vladimir Putin, in an attempt to halt Ukrainian advances.
The hasty mobilisation drive has caused anger across the country and triggered an exodus of hundreds of thousands of Russians unwilling to participate in the war.
At a press conference in the Kazakhstan capital of Astana on Friday, Putin said that 16,000 mobilised troops were already fighting in Ukraine, and that 222,000 Russians had already been called up.
According to local reports, more than 20 newly mobilised soldiers have already been killed fighting in Ukraine.
During training, one man at a military base near St Petersburg fatally shot himself. Another in Siberia reportedly cut his own throat in a mess hall.
