Polish border guards detained Ihor Mazur, a high-ranking member of the far-right nationalist UNA-UNSO group, on November 9 at the Dorohusk-Jahodin border crossing based on an international arrest warrant that Russia requested through Interpol.
He is wanted on charges of terrorism for allegedly fighting against Russian federal forces in the First Chechen War in 1994-95 and for being a member of two Ukrainian groups that Moscow considers "extremist."
Mazur said he was planning on attending a conference in Warsaw but was taken to Chelm, where on November 10 Polish prosecutors questioned him for three hours before releasing him on bail to the Ukrainian Consulate in Lublin.
He can move freely in the Lublin region, but must be chaperoned by a Ukrainian consul beyond the administrative district.
Artem Valakh, the consul in Lublin, told reporters that since November 11 is a public holiday in Poland, the extradition hearing will start mostly likely on November 12.
Mazur has told Ukrainian media that he was a correspondent for the Vilniy Kavkaz (Free Caucasus) press center during the early stages of the First Chechen War and that he never fought in it on either side.
He is a longtime member of UNA-UNSO and formerly headed the Kyiv regional branch of Praviy Sektor (Right Sector), another nationalist group.
Russia's Supreme Court on November 17, 2014 ruled that both organizations are "extremist."
The same year, the Russian Investigative Committee initiated criminal proceedings into members of UNA-UNSO. They include ultranationalist Dmytro Korchynskiy, former Right Sector leader and lawmaker Dmytro Yarosh, and Oleh Tyahnybok, a former lawmaker in the nationalist Svoboda party.
"Depending on the role of each, they are suspected of committing crimes" related to creating an "armed group (gang) in order to attack citizens, the leadership of such a group (gang), and participation in the attacks committed by it," Russian state TASS news agency reported.
Ukrainian Interior Minister Arsen Avakov over the weekend accused Moscow of misusing Interpol for politically motivated persecution.
On November 10, Avakov said he wrote the head of Interpol an official letter stating that Russia violated two statutes of the international police organization's charter that forbid unsubstantiated prosecution, and interference in military, political, religious, and racial issues.
Mazur fought in the Donbas war against Russia-backed separatists starting in May 2014. He became an armed forces officer in April 2015, then a company commander and was the deputy chief of staff of the intelligence battalion in the southern Donetsk region before his discharge in November 2016.
Previously, Mazur headed Right Sector in the Kyiv region and was part of a self-defense unit during the pro-democracy Euromaidan protests that led to the ouster of former Moscow-friendly President Viktor Yanukovych.
He currently is the deputy chairman of the UNA-UNSO party.