The first Russian soldier to be tried for war crimes in Kyiv since the start of the Ukraine war has asked for "forgiveness" in court.

"I know that you cannot forgive me, but I still ask for forgiveness," said 21-year-old Vadim S. at the hearing in Kyiv on Thursday to the wife of the 62-year-old civilian whose killing he had already confessed to.

S. is accused of having shot the unarmed man in a stolen car on February 28 in the northern Ukrainian village of Chupakhivka.

When asked in court if he pleaded guilty, he replied "yes."

The soldier from Irkutsk, Siberia faces a life sentence for war crimes and murder.

According to Ukrainian investigators, the young man wanted to flee with four comrades in a stolen car after an attack on his unit in northern Ukraine.

The victim witnessed the theft of the car.

S. confirmed this representation in court.

Another Russian soldier in the car, who was not his commander, "told me to shoot," he said.

"He started saying in a forceful tone that I should shoot (and) that I would create a danger if I didn't." He fired at the civilian at close range.

"It killed him."

Ukraine has accused the Russian army of committing numerous war crimes and crimes against humanity since the invasion began on February 24.

War crimes trials of two other Russian soldiers are scheduled to begin later Thursday.

The International Criminal Court (ICC) is also investigating alleged international crimes.