DNR military commander Aleksandr Khodakovsky claimed on November 5 that Russian friendly fire may have caused up to 60% of total Russian losses since the end of Russian offensive operations in Mariupol in mid-May
https://www.understandingwar.org/backgrounder/russian-offensive-campaign-assessment-november-5
https://www.understandingwar.org/backgrounder/russian-offensive-campaign-assessment-november-5