This is reported by her lawyers on Twitter, Censor.NET reports.
"On Jan. 15 the FSB opened a case against Nadiia Savchenko for illegal border crossing. She was informed of that today. Savchenko herself is currently being transferred to the prison hospital of Matrosskaya Tishyna. These office bastards did not only kidnap Savchenko from Ukraine, but now they are cooking up a case of alleged illegal border crossing, " Nikolay Polozov tweeted.
"Savchenko is being transferred to the prison hospital to deprive her of her communication with lawyers and to allow FSB pressure with the second case," he added.
"This is a response to yesterday (sanctions against the Russian delegation to PACE. - ed.). They really did open a case against Savchenko for illegal border crossing. They brought her themselves and they charged her. At the moment, Nadiia Savchenko is being transferred to Matrosskaya Tishyna ..." another lawyer Mark Feygin tweeted.