STORY: Vadim Shishimarin, a 21-year-old Russian tank commander is charged with murdering a 62-year-old civilian in the northeast Ukrainian village of Chupakhivka on Feb. 28.
He pleaded guilty and could face a life sentence.
Ukrainian state prosecutors have said the soldier and four other Russian servicemen fired at and stole a private car to escape after their column was targeted by Ukrainian forces.
The Russian soldiers drove into the village of Chupakhivka where they saw an unarmed resident riding a bicycle and talking on his phone, they said.
They said Shishimarin was ordered by another serviceman to kill the civilian to prevent him reporting on the Russians' presence and fired several shots through the open window of the car with an assault rifle at the civilian's head. The civilian died on the spot.
Kyiv has accused Russia of atrocities and brutality against civilians during the invasion and said it has identified more than 10,000 possible war crimes.
Russia has denied targeting civilians or involvement in war crimes and accused Kyiv of staging them to smear its forces.