Russia’s most powerful mercenary, Yevgeny Prigozhin, said on Wednesday that he had asked prosecutors to investigate whether senior Russian defence officialshad committed any “crime” before or during the war in Ukraine.

Prigozhin’s request is his most blatant public challenge to date against President Vladimir Putin’s top military brass, defence minister Sergei Shoigu and chief of the general staff Valery Gerasimov.

The 61-year-old restaurateur-turned-mercenary has spent months insulting both Shoigu and Gerasimov, who are leading Russia’s war effort, for alleged treachery. Neither has responded publicly to his criticism.

“Today I have sent letters to the Investigative Committee and the Prosecutor’s Office of the Russian Federation with a request to check on the fact of the commission of a crime during the preparation and during the conduct of the SMO (Special Military Operation) by a host of senior functionaries of the Defence Ministry,” Prigozhin said.

“These letters will not be published due to the fact that the investigative authorities will deal with this.”

Prigozhin’s private army, the Wagner group, has been fighting alongside Russia’s regular forces in Ukraine and spearheaded the months-long assault on the eastern city of Bakhmut.