Ukraine’s security service on Wednesday announced the capture of a Russian army major who was allegedly delivering explosives to pro-Kremlin rebels in the east.

Ukraine's security service on Wednesday announced the capture of a Russian army major who was allegedly delivering explosives to pro-Kremlin rebels in the east.

Moscow denies any involvement in Ukraine's 15-month conflict and describes Russians caught in the war zone as "volunteers" who joined the fighting without any direct orders from the army.

The National Security Service of Ukraine (SBU) identified the Russian allegedly captured in the Donetsk region at the weekend as Vladimir Starkov -- an army major who got lost while driving a truck filled with explosives to a guerrilla outpost.

"Starkov immediately confessed to being a Russian citizen and to being an enlisted soldiers of the Russian armed forces," SBU chief Vasyl Grytsak told reporters.

Ukraine in May showed off two captured Russians who identified themselves as acting servicemen sent on a reconnaissance mission by their military intelligence command.

Russia claims the two had quit the force by the time they joined the fighting in the former Soviet state.