Russia's FSB security service has opened a criminal case against a journalist working for CNN who it said had illegally crossed the Russian border to film a report inside the Kursk region, the Interfax news agency reported on Thursday. Interfax named the journalist as Nick Paton Walsh, a British citizen. It said the FSB had also opened similar cases against two Ukrainian journalists. Interfax cited the FSB as saying Moscow would soon issue an international arrest warrant related to the cases. The maximum punishment for anyone found guilty of illegally crossing the border is five years in jail, it said.