President Putin warns the West he’s not bluffing and that he is prepared to use "all the means at our disposal" if Russian territory is threatened. The nuclear threat came as he announced a “partial” mobilisation of reserve troops to Ukraine. Vitaly, Victoria and the BBC’s Security Correspondent Frank Gardner unpick how real the possibility of a nuclear war actually is. Ukrainecast’s Ivana Davidovic talks to a recent graduate from St Petersburg, who says he wants to leave Russia to avoid being drafted into the military. And he’s not alone - Olga Ivshina from the BBC’s Russian Service says flights out of the country to visa-free destinations sold out in a day. Also, Vladimir Osechkin, the founder of the prisoners’ rights organisation Gulagu.Net, tells us that someone recently tried to assassinate him while he was at home with his family. The series producer is Estelle Doyle. The producers are Ivana Davidovic and Arsenii Sokolov. The planning producer is Louise Hidalgo. The technical producer is Dafydd Evans. The assistant editor is Alison Gee. The editor is Jonathan Aspinwall. Email Ukrainecast@bbc.co.uk with your questions and comments. You can also send us a message or voice note via WhatsApp, Signal or Telegram to +44 330 1239480.