At least 11 people, most of them high-ranking officers, died in a military helicopter crash near the Russian city of Vladikavkaz, officials said on Tuesday.
The Mi-8 transport helicopter crashed late Monday in a forest south of Vladikavkaz, in Russia's troubled North Caucasus region.
"Eleven people died and four have been hospitalised -- one in serious condition, one in less serious condition," Colonel Alexander Drobyshevsky, an aide to Russia's air force commander, said on NTV television. "The fate of one more serviceman is being checked".
Other officials were quoted by Russian news agencies as saying 12 people had been confirmed dead.
Interfax news agency quoted a source in the North Caucasus military district headquarters as saying that 12 had died, including three generals, six colonels, two lieutenant colonels and a major.
A report from RIA Novosti news agency quoted the region's military prosecutor as saying that only two generals had died.
The helicopter had been taking part in military exercises, Russian news agencies said.
The cause of the accident remains under investigation, but officials suspect the aircraft struck a tree while flying at low altitude in poor visibility, RIA Novosti reported.
ORT television showed footage of the partially burnt wreckage scattered in dense forest.