Russia has detained a French citizen for illegally entering the country from Estonia and opened a criminal investigation, the Federal Security Service (FSB) said Tuesday. EU and Nato member Estonia shares a 300-kilometre long (185 miles) border with Russia. "The foreigner admitted that he illegally crossed the state border of the Russian Federation, bypassing the established checkpoints from Estonia to Russia by boat across the Narva River," the FSB said in a statement.