Russian Ministry of Defence has revealed that 498 Russian Servicemen died since Thursday when President Putin ordered the invasion of neighbouring Ukraine.
The ministry added that 1597 more Russian servicemen were injured.
The ministry did not explain the nature of the injuries.
The heavy losses indicated that the Russian forces are not a walk in the park in their invasion.
Ukrainian authorities said their citizens are resisting the invaders.
Seeking to play down its casualties, the defence ministry stressed that reports of “incalculable” losses among the Russian military are fake and deliberately spread by the media.
The Defence Ministry’s spokesman, Igor Konashenkov, said that reports that Russia had used conscripts and cadets of the military institutions in the operation are also false.
On 27 February, Ukraine claimed Russian forces lost about 4,300 servicemen during their invasion of Ukraine.
Deputy Defence Minister Hanna Malyar also said on her Facebook page that Russian troops lost about 146 tanks, 27 aircraft and 26 helicopters.
Putin on 24 February ordered what he called a special military operation into Ukraine.
The declared goals of operation are demilitarization and denazification of Ukraine, as well as defence of the Donbass republics.
But the operation has turned out to be a full scale war, for which Russia is now being isolated by the world.