Ukraine's HUR says Russian Su-57 damaged in engine fire at Akhtubinsk airfield
Agency suggests deteriorating jet fuel quality linked to Ukrainian refinery strikes may be behind the blaze
Ukraine's military intelligence agency (HUR) confirmed that a Russian Sukhoi Su-57 fifth-generation fighter jet was damaged by an engine fire at Akhtubinsk airfield in Russia's Astrakhan Oblast on Oct. 29, suggesting the fire may have resulted from deteriorating jet fuel quality linked to Ukrainian long-range drone strikes on Russian oil refineries.