Russian authorities have launched a fresh investigation targeting a former teacher in Russia's western region of Oryol who was convicted of inciting ethnic hatred and sacked from his job for writing a pro-Ukraine poem.

Russia's state-run Interfax news agency quoted Aleksandr Korgin, an official in Oryol's regional Investigative Committee, as saying that the investigation targets Aleksandr Byvshev.

Korgin said linguistics experts had concluded that one of Byshev's poems about Soviet-era poet and Noble Prize laureate Joseph Brodsky contains "extremist connotations."

Korgin said Byvshev may be charged with inciting ethnic hatred in the case.

Byvshev was found guilty of inciting ethnic hatred in 2015 after his poem "To Ukrainian Patriots" circulated in the Internet.

He was then deprived of the right to teach for two years and sentenced to 300 hours of community service.

Based on reporting by Interfax