President Volodymyr Zelensky has blasted as a "farce" the referendums in occupied areas of Ukraine where 99% voted to join Russia and vowed to continue fighting to reclaim the land that has been lost despite a nuclear threat.
Russian-installed officials in four occupied regions of Ukraine reported huge majorities of votes in favour of joining Russia as the United States planned a UN resolution condemning the referendums as shams.
There is a fear now that Vladimir Putin could use nuclear weapons to defend the regions if he claims that an attack on them is an attack on Russia itself.
But Zelensky said that the elections could never be seen as legitimate.
"This farce in the occupied territories cannot even be called an imitation of a referendum," Zelensky said in a nightly video address.
He said Ukraine would defend its people still living under occupation in the four areas where votes were held - Donetsk, Luhansk, Zaporizhzhia and Kherson regions - and in parts of Kharkiv region still under occupation.
The president also said there would soon be good news from the front, but offered no details for the moment. "We are advancing and will liberate our land," he added.
A hastily arranged referendum took place over five days in the eastern regions and vote tallies from complete results on Tuesday in the four provinces ranged from 87% to 99.2% in favour of joining Russia, according to Russia-appointed officials.
The head of the upper house of the Russian parliament said the chamber might consider annexation on October 4.
"The results are clear. Welcome home, to Russia!," Dmitry Medvedev, a former president who serves as deputy chairman of Russia's Security Council and an ally of President Vladimir Putin, said on Telegram.
But US envoy Linda Thomas-Greenfield said the United States will introduce a resolution at the United Nations Security Council calling on member states not to recognise any change to Ukraine and obligating Russia to withdraw its troops.
"Russia's sham referenda, if accepted, will open a Pandora's box that we cannot close," she said at a council meeting.
Over a looming nuclear threat, Putin said last week he was willing to use the weapons to defend the "territorial integrity" of Russia, and Medvedev issued a new nuclear warning on Tuesday to Ukraine and the West.
But Mykhailo Podolyak, an adviser to Zelensky, said that Kyiv would not be swayed by nuclear threats or by the annexation votes, and would press on with plans to retake all territory occupied by invading Russian forces.
Diplomats say the nuclear sabre-rattling is an attempt by Moscow to scare the West into reducing its support for Kyiv.
For the first time Medvedev predicted that the NATO military alliance would not directly enter the Ukraine war even if Moscow struck Ukraine with nuclear weapons.
