One of Vladimir Putin's closest allies has warned "there is no going back" and Russia is prepared to use its most powerful nuclear weapons to defend what it calls "new territories" in Ukraine.
Dmitry Medvedev, former Russian president and prime minister, and currently deputy chairman of the Security Council of Russia, has issued a chilling message on Telegram - a messaging app similar to Whatsapp.
His outburst come as Russia launched a series of referendums in four occupied areas of Ukraine today, which it is expected Moscow will use as a reason to justify annexation.
