HELSINKI (AP) — A man has gone on trial in Finland on charges of war crimes allegedly committed against Ukrainian forces in a Russia-backed separatist region of Ukraine in 2014.

Prosecutors are seeking life imprisonment for the defendant at the trial which opened Thursday at the Helsinki district court, public broadcaster YLE reported.

The suspect's name was not given when the charges were announced, but Finnish media have identified him as Russian national Yan Petrovsky, who had been living in Finland under the alias Voislav Torden.

His lawyer, Heikki Lampela, said he would deny all the charges.

The suspect was arrested in July 2023 at Helsinki Airport as he was headed for Nice, France, with his family.

Finland’s Supreme Court ruled he could not be extradited to Ukraine, where he faced an arrest warrant, due to the risk of inhumane prison conditions there. Finnish prosecutors said that the Nordic country has an obligation to try him.

Prosecutors said when they announced the charges on Oct. 31 that they are related to his alleged activities in a unit called Rusich, which fought for the Russian-backed Luhansk separatist region against Ukrainian forces. They said the defendant is “accused of having participated, as the unit’s deputy commander, in acts that violate the laws of war, in which he and the unit’s soldiers have killed a total of 22 Ukrainian soldiers and seriously wounded four.”

He is also accused of “acts contrary to the laws of war regarding the way of warfare and the treatment of wounded and killed enemy soldiers.”

In March 2014, Russia annexed Ukraine’s Crimean Peninsula. Separatist forces backed by Moscow later began an uprising in the eastern Ukrainian region, known as the Donbas, which grew into a long-running conflict. Russia launched its full-scale invasion of Ukraine in February 2022.