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.
Ukraine officials have warned that Ukrainians were told the voting was mandatory with residents being threatened with punishment if they did not take part.
Mr Medvedev's message read: "Referendums will be held, and the Donbas republics and other territories will be admitted to Russia.
"The protection of all the territories that have joined will be significantly strengthened by the Russian armed forces.
"Russia announced that not only mobilisation capabilities, but also any Russian weapons, including strategic nuclear weapons and weapons based on new principles, could be used for such protection.
"Therefore, various retired idiots with generals’ stripes do not need to scare us with talk about a Nato strike on Crimea.
"Hypersonic is guaranteed to be able to reach targets in Europe and the United States much faster.
"But the western establishment, in general, all citizens of the Nato countries need to understand that Russia has chosen its own path.
"There is no way back."
Russia's seven-month war has killed tens of thousands, uprooted millions and pummelled the global economy.
Earlier this week Putin announced a military draft to enlist 300,000 troops to fight in Ukraine, as the Kremlin tries to regain the upper hand in the grinding conflict.
The referendums had been discussed for months by Moscow-installed authorities in the four regions but Ukraine's recent victories prompted a scramble to schedule them.
Voting in the provinces of Luhansk, Donetsk, Kherson and Zaporizhzhia, representing about 15% of Ukrainian territory, is due to run from Friday to Tuesday.
"Voting has started in the referendum on Zaporizhzhia region becoming a part of Russia as a constituent entity of the Russian Federation!
"We are coming home! Godspeed, friends!" Vladimir Rogov, an official in the Russian-backed administration
of that southern region of Ukraine, said.
The referendums have been widely condemned by the West as illegitimate and a precursor to illegal annexation.
There will be no independent observers, and much of the pre-war population has fled.
The Organisation for Security and Cooperation in Europe (OSCE), which monitors elections, said the outcomes would have no legal bearing as they do not conform with Ukraine law or international standards and the areas are not secure.
