TOPSHOTS A Ukrainian radical nationalist group Praviy Sektor (Right Sector) volunteer fighter fires his assault rifle during 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