CIA-UAP-011, The Sary Shagan Weapons Testing Range
This CIA Intelligence Information Report from December 1973 provides information on the Soviet Sary Shagan Weapons Testing Range, including details about its facilities, weapons systems (System-75 SA-2 and System-300/Aldan warheads), rumored laser weapon research, and unidentified aerial phenomenon observed at the site. A more redacted version of this report has been available on CIA's public website.
View the file on war.gov