(ANSA-AFP) - KYIV, SEP 27 - Annexation polls organised by Kremlin-installed authorities in four regions of Ukraine mostly controlled by Russian forces were due to close Tuesday, with Moscow's threats of nuclear weapons looming. Kyiv and its allies have denounced the votes as a sham and said the West would never recognise the results of the ballots which are ratcheting up the stakes of Russia's seven-month invasion. Russian forces in Ukraine this month have suffered serious setbacks, both in the east and south of the country, which observers say pushed President Vladimir Putin to rush ahead with the vote to cement Moscow's authority there. Putin said Russia would use any and all available means to defend its territory, implying that after the four regions were annexed Moscow could deploy strategic nuclear weapons to repulse Ukrainian attempts to take back the territory. He also announced that Moscow was calling up 300,000 reservists, a move that sparked some protests and saw Russian men fearing deployment to Ukraine flee to neighbouring countries. (ANSA-AFP).