Young men from the Novorossiisk Cossack Cadet Corps in the Krasnodar region originally made the video for the popular humor show and contest KVN in 2011, but the recording was not made public at that time, head of the cadet academy Andrei Laktyushkin said, TASS news agency reported Thursday.
After the video appeared online, "we got in touch with those alumni who graduated back in 2012, and they say they never posted that recording anywhere," Laktyushkin was quoted as saying.
Now the prosecutor's office in Krasnodar wants to know how the years-old video appeared on YouTube shortly before Russia's grand-scale celebrations of Victory Day on May 9.
"Orders have been issued to sort out who posted the recording on the Internet, and to look into it," a spokesman for the prosecutor's office was quoted by TASS as saying.
In the video, young men in military uniforms say they intend to "break stereotypes about it being difficult to serve in the army."
Then, stripped to their underpants, they climb atop a T-34 tank, rubbing its cannon and pretending to soap up its sides in a provocative dance that includes several moments of twerking.
In another recent case, a court in Novorossiisk, where the cadet academy is located, handed down sentences last month ranging from fines to 15 days in jail to several young women for twerking in front of a World War II monument.
Shortly before that, a troupe of teenage girls dressed up like bees in the Urals city of Orenburg caused a buzz after a video of them twerking in a dance school performance was posted on the Internet.