Doka Itslayev, a lawyer for Ukrainian Mykola Karpiuk convicted in Russia, said his client is ready to file a request for pardon.

"Nothing will change if he writes this application. We have generally agreed that he will sign all the necessary documents that will need to be signed," Itslayev said on a program on hromadske.tv.

He also said Karpiuk can be handed over to Ukraine under the Convention on the Transfer of Sentenced Persons and his sentence can be contested in the European Court of Human Rights, which the lawyer finds to be a promising option.

"I can say with confidence that the chances of winning this case in the European Court are very high, but I really hope that we will resolve this issue much faster," Itslayev said.

The lawyer said Karpiuk's pardon and exchange are more preferable.

According to earlier reports, the Supreme Court of Chechnya in late May sentenced Karpiuk to 22.5 years in prison and Ukrainian citizen Stanislav Klykh to 20 years in prison for killing Russian troops and participating in a gang on the side of militants in the first Chechen war.

According to Russian investigators, Klykh and Karpiuk were members of the Ukrainian National Assembly-Ukrainian People's Self-Defense (UNA-UNSO) group and fought on the side of armed units of the self-proclaimed republic of Ichkeria against Russian federal forces in 1994-1995. According to investigators, they fought against Russian troops in Grozny.