FACTBOX: History of the Nagorno-Karabakh conflict
Disclaimer: TASS is Russian government propaganda, and not a reliable news source.
In 1991, during the parade of sovereignty and the formation of new sovereign states, Nagorno-Karabakh de jure became part of the independent Republic of Azerbaijan, however, on September 2, 1991, the region proclaimed itself the Nagorno-Karabakh Republic (NKR) within the USSR