Mark Feygin, the lawyer of Ukrainian citizen Nadia Savchenko who has been found guilty in Russia of murdering Russian journalists, has appealed to the UN Working Group on Arbitrary Detention (WGAD) and the UN Special Rapporteur on Human Rights Defenders.

"The refusal to file an appeal excludes the ECHR cassation option. Although I disagree with Nadia on this matter, I have taken some precautions and have launched a number of international procedures towards her release," he wrote on Facebook.

The first procedure is underway at the UN Working Group on Arbitrary Detention, he said.

"I have brought the Savchenko case there, and I am expecting results in April," he said.

In addition, the lawyer appealed to the UN Special Rapporteur on Human Rights Defenders.

Feygin said earlier that Savchenko had no intention of challenging the guilty verdict.

"That's her decision; she believes that the refusal to file an appeal will boost the negotiations and her extradition to Ukraine," the lawyer said.