Ukraine called the emergency meeting of the Security Council to respond to the referendums and the expected annexation announcements from Russia.
"Any annexation in the modern world is a crime, a crime against all states that consider the inviolability of border to be vital for themselves," Zelenskyy said.
He accused Russia of destroying "the main body of international law", and responding to "any proposals for talks with a new brutality on the battlefield, with even greater crisis and threats to Ukraine and the world".
"Russia's recognition of these sham referenda as normal, the implementation of the so-called Crimean scenario and another attempt to annex Ukrainian territory, will mean there is nothing to talk about with this president of Russia," Zelenskyy said.
"Annexation is the kind of move that puts him alone against the whole of humanity."
Many Security Council members denounced the referendums and stressed that any annexation of territory would never be recognised.
UN political chief Rosemary DiCarlo said voting on the referendums took place in polling centres and "de facto authorities accompanied by soldiers also went door-to-door with ballot boxes".
"They cannot be called a genuine expression of the popular will," she told the council.
"Unilateral actions aimed to provide a veneer of legitimacy to the attempted acquisition by force by one state of another state's territory, while claiming to represent the will of the people, cannot be regarded as legal under international law."
Britain's deputy ambassador, James Kariuki, called the referendums "illegal and illegitimate" and a violation of Ukraine's sovereignty and territorial integrity and the principles of the UN Charter.
Albanian Ambassador Ferit Hoxha said the referendums are a replay of the script Russia used in Crimea, are against the Ukrainian constitution and "have nothing to do with democracy, nothing to do with the free will of Ukrainians".
US Ambassador Linda Thomas-Greenfield announced that the US and Albania will soon circulate a Security Council resolution that would condemn "the sham referenda", call on all countries not to recognise any altered status of Ukraine, and demand an immediate withdrawal of Russian troops from the country.
The resolution is certain to face a Russian veto, "but we're hoping to see the rest of the council stand strong and refusing to accept the redrawing", she said.
The US ambassador said she expects a Security Council vote on the resolution late this week or early next week.
Thomas-Greenfield said if Russia does use its veto, the US and Albania will take the resolution to the 193-member UN General Assembly, where there are no vetoes, "to send an unmistakable message to Moscow".
The assembly overwhelmingly adopted two resolutions in March, with support from about 140 countries, demanding an immediate end to Russia's military operation and withdrawal of its forces, and blaming Moscow for the humanitarian crisis that has now hit many countries, especially in the developing world with food and energy shortages, higher prices and rising inflation.
Explaining why the US was moving ahead with the resolution, Thomas-Greenfield quoted US President Joe Biden speaking to the annual meeting of world leaders at the General Assembly last week and saying "if nations can pursue their imperial ambitions without consequences, then we put at risk everything that this institution stands for everything".
Russia's UN ambassador, Vassily Nebenzia, claimed that 100 independent international observers from 40 countries observed the referendums, "and they were particularly surprised by the enthusiasm of the people".
He accused Ukrainian forces of using Western "military might" in stepping up artillery strikes and shelling towns where there was a referendum "to sow panic among citizens and to make vain attempts to undermine the vote".
Nebenzia claimed the West's aim in supporting Ukraine and coming up to Russia's borders "is to weaken and bleed dry Russia as much as possible".
"Their dream is to break up Russia and subject it to its own will," he said.
Alluding to the possibility of more referendums and annexations, he called the situation in Ukraine "dire" and claimed Kyiv had been rejected not only by the people of Crimea and Donbas but the Kherson and Zhaporizhzhia regions.
"This process is going to continue if Kyiv does not recognise its mistake and its strategic errors and doesn't start to be guided by the interests of its own people, and not blindly carry out the will of those people who are playing them," Nebenzia said.
Thomas-Greenfield, the US ambassador, responded, "I have no doubts in my mind that they will attempt to do it."
She reiterated Biden's unwavering support for Ukraine, saying "that's why it's so important that we stand against this immediately - and that we will do".l
- AP
