In a big move, Russian President Vladimir Putin on Friday formally announced the annexation of four regions - Donetsk, Luhansk, Kherson and Zaporizhia and claimed that "this is the will of millions of people," media reports said.

"There are four new regions of Russia," Putin said in a lengthy speech declaring the annexation of Ukrainian territories in the St George's Hall at a Kremlin ceremony. The speech was filled with highly critical rhetoric about Ukraine and its Western allies, reported Al Jazeera. Putin said the residents in the four annexed regions will now be Russia's "citizens forever".

While denying seeking revival of the Soviet Union by the said annexation, Putin accused Western states - which have imposed sweeping sanctions on Moscow over its invasion of Ukraine.

Moreover, in a strong statement, Putin also added that Russia would now defend its new territory "with all the means at its disposal."

Defending its decision to go ahead with the referendum and announce the annexation of the region, the Russian President argued it was the "integral right" of people in Donetsk, Luhansk, Kherson and Zaporizhia to join Russia, reported Al Jazeera.

Speaking further, Putin claimed that the people in eastern Ukraine made up of Donetsk and Luhansk - had been "victims of inhumane terrorist attacks conducted by the Kyiv regime".

He also called the result of the referendum "the will of millions of people."

In a major move by Russia, President Vladimir Putin had signed a decree recognizing the so-called "independence" of the Ukrainian regions Zaporizhzhia and Kherson.

Moreover, the UN Security Council is set to vote Friday on a resolution that would seek to condemn Russia for its referenda in four regions under Russian control but claimed by Ukraine, media reports said.

The US-sponsored resolution would call on all countries not to recognise the change in the status of the four regions, CNN reported. The resolution, which is also backed by Albania, would reaffirm the UN commitment to Ukraine's sovereignty and territorial integrity.

UN Secretary-General Antonio Guterres said any annexation of a state's territory by another state resulting from a "threat or use of force" is a violation of the UN charter and international law.

"In this moment of peril, I must underscore my duty as Secretary-General to uphold the @UNCharter. The charter is clear. Any annexation of a state's territory by another state resulting from the threat or use of force is a violation of the Principles of the Charter & international law," Guterres tweeted.

On Thursday, US Secretary of State Antony Blinken accused Russia of the annexation of Ukrainian territories and called it illegal under international laws, media reports said. Describing Russia's move as an act of 'land grab', the top US diplomat said that the US will never recognise the annexation by Moscow.

"The Kremlin's sham referenda are a futile effort to mask what amounts to a further attempt at a land grab in Ukraine," Blinken said in a statement.

(With inputs from ANI)