Washington: US Secretary of State Antony Blinken on Thursday 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', Blinken 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, Al Jazeera reported.

After Kremlin said that the annexation of four parts of Ukraine would be announced on Friday, the UN Secretary-General Antonio Guterres said that 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 a tweet, Guterres wrote, "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 & int'l law."

This comes after Russian President Vladimir Putin's spokesman Dmitry Peskov said that Russia will hold a signing ceremony on Friday to incorporate the annexed four occupied regions of Ukraine.

"Tomorrow in the Georgian Hall of the Grand Kremlin Palace at 15:00 [1200 GMT] a signing ceremony will take place on the incorporation of the new territories into Russia," spokesman Dmitry Peskov said on Thursday, as quoted by Al Jazeera.

He further added that Putin will make a speech at this event. The referendum by the Russian authorities on the annexation of occupied territories of Ukraine was largely seen as a "sham referendum" and has been widely criticised by various countries.

German Chancellor Olaf Scholz said that Germany will never accept the results of "sham" referendums on joining Russia in occupied regions of Ukraine.

According to Al Jazeera, Scholz made these remarks in conversation with Ukrainian President Volodymyr Zelenskyy. Scholz reaffirmed Germany's stance saying that the country's support to Ukraine remains unwavering.

Meanwhile, Canada also said that they will not recognise Russia's attempted illegal annexation of Ukrainian territories. "Canada does not and will not ever recognise the results of these sham referendums or Russia's attempted illegal annexation of Ukrainian territories," Canadian Prime Minister Justin Trudeau said in a statement.