The first war crimes trial since Moscow's invasion of Ukraine, against a Russian soldier accused of killing a civilian, opens in Kyiv on Wednesday.
The trial, expected to be followed rapidly by others, will test the Ukrainian justice system at a time when international institutions are conducting their own investigations into abuses allegedly committed by Russian forces.
Vadim Shishimarin, 21, will appear at a district court in Kyiv from 2:00 pm (1100 GMT) over the death of a 62-year-old man in north-eastern Ukraine on February 28, just four days into the Russian invasion.
Charged with war crimes and premeditated murder, the soldier from Irkutsk in Siberia faces a possible life sentence.
The Kremlin said Wednesday it was not informed about the case.
"We still have no information. And the ability to provide assistance due to the lack of our diplomatic mission there is also very limited," Kremlin spokesman Dmitry Peskov said.
Shishimarin's lawyer, Viktor Ovsiannikov, told AFP that the Russian soldier "understands what he is being accused of", without revealing the case for the defence.
Ukrainian authorities say he is cooperating with investigators and admits killing the civilian.
Prosecutors say Shishimarin was commanding a unit in a tank division when his convoy came under attack.
He and four other soldiers stole a car, and as they travelled near the village of Chupakhivka in the Sumy region, they encountered a 62-year-old man on a bicycle.
"One of the soldiers ordered the accused to kill the civilian so that he would not denounce them," the prosecutor's office said.
Shishimarin then fired a Kalashnikov assault rifle from the window of the vehicle and "the man died instantly, a few dozen metres from his home", they added in a statement.
In early May, Ukrainian authorities announced his arrest without giving details, while publishing a video in which Shishimarin said he had come to fight in Ukraine to "support his mother financially."
He explained his actions saying: "I was ordered to shoot, I shot him once. He fell and we continued our journey."
- 'Clear signal' -
The case is proving challenging, according to his lawyer.
"This is the first such case in Ukraine with such an indictment. There is no relevant legal practice or verdicts on such cases. We will sort it out," he said.
Ovsiannikov said he had not seen any rights violations by the authorities.
Ukraine's chief prosecutor Iryna Venediktova underlined the importance of the case for her country in a series of tweets.
"We have over 11,000 ongoing cases of war crimes and already 40 suspects," she said.
"By this first trial, we are sending a clear signal that every perpetrator, every person who ordered or assisted in the commission of crimes in Ukraine shall not avoid responsibility."
Oleksandr Pavlichenko, the head of the Ukrainian Helsinki Group for Human Rights, said that in the Shishimarin case "the motivation is not only legal, but political as well."
What is at stake, he said, is whether Ukraine "will have a real judicial process or just a play for the public."
This will depend, Pavlichenko said, on Shishimarin's fate after the verdict: whether he will serve a sentence in Ukraine or be exchanged in a prisoner swap.
Two other Russian servicemen are due to go on trial in Ukraine on Thursday for firing rockets at civilian infrastructure in the north-eastern Kharkiv region.
