Kremlin critic Alexei Navalny, who is serving a two-and-half-year jail term in a penal colony outside Moscow, said Monday he was locked up in a "real concentration camp". "I have to admit that the Russian prison system was able to surprise me. I had no idea that it was possible to arrange a real concentration camp 100 km from Moscow," Navalny posted on Instagram along with a photo of himself with a close-cropped haircut. He added that he was in Penal Colony No. 2 in the town of Pokrov in the Vladimir region. emg/acl/jj