A Russian serviceman has shot dead eight fellow soldiers and injured at least two more on a military base in the country's Far East, officials say.
The soldier - who has been detained - might have been suffering from mental health problems, they said.
The shooting happened in the village of Gorny, not far from the city of Chita, on Friday evening.
The soldier - whose name has not been released - was guarding the base at the time. He is believed to be a conscript.
The shooting happened at 18:20 local time (11:20 GMT) during a change of guard at the base in the Transbaikal region, the Russian defence ministry said.
Russian media report that two officers and six conscripts were killed.
A special commission led by Deputy Defence Minister Andrey Kartapolov is flying to the region to investigate the shooting.
Military service is mandatory in Russia for all male citizens aged 18-27. They typically serve 12 months, and can then sign a professional contract to continue in the armed forces.
In the mid-2000s, rights groups reported widespread violence and bullying - known as "dedovshchina" - against new conscripts in the Russian armed forces.
But in recent years, Russia has prided itself for modernising the military and rooting out bullying.