The official figure for Russian military deaths is 5,732, while most estimates put the number between 3,500 and 7,500, or even as high as 14,000.
Although there are no accurate figures for the number of Chechen forces killed, various estimates put the number at about 3,000 to 17,391 deaths and missing.
The Chechens' subsequent attempts at gaining independence after the 1917 fall of the Russian Empire failed, and in 1922 Chechnya became part of Soviet Russia and in December 1922 part of the newly formed Soviet Union (USSR).
In 1936, Soviet leader Joseph Stalin established the Chechen-Ingush Autonomous Soviet Socialist Republic.
Animal welfare organisations expressed outrage at news that the Russians have sent a dog into outer space.