Cherkas, a russian citizen and volunteer with the Praviy Sektor (Right Sector) fighters, crawls under barbed wire during a personal training at the Praviy Sektor   headquarters   in a small village near Pokrovskoe, eastern Ukraine, on June 4, 2015. Praviy Sektor is a paramilitary group fighting alongside the regular army against separatists in the east of Ukraine. Ukrainian President Petro Poroshenko warned on June 4 of a "colossal threat" of renewed fighting with pro-Russian rebels after a surge in violence that left at least 26 people dead.  AFP PHOTO / FABIO BUCCIARELLI        (Photo credit should read FABIO BUCCIARELLI/AFP/Getty Images)