Group of Seven foreign ministers said on Friday they would "never recognise" Russia's annexation of four more regions in Ukraine and pledged further sanctions against Moscow.

President Vladimir Putin's efforts to annex the Donetsk, Luhansk, Kherson and Zaporizhzhia regions "constitute a new low point in Russia's blatant flouting of international law", the ministers said in a statement, calling the regions "integral parts of Ukraine".

"We will never recognise these purported annexations, nor the sham 'referenda' conducted at gunpoint," they said.

"We will impose further economic costs on Russia, and on individuals and entities – inside and outside of Russia – that provide political or economic support to these violations of international law."

The foreign ministers of Britain, Canada, France, Germany, Italy, Japan, and the United States as well as the High Representative of the European Union called on "the broader international community to reject Russia's brutal expansionism".

They said they were "united in our condemnation in the strongest possible terms of Russia's war of aggression against Ukraine and its continued violations of Ukraine's sovereignty, territorial integrity and independence".

The ministers added they were "unwavering" in their support for "Ukraine's right to defend itself" as well as "its unquestionable right to reclaim its territory from Russia".

Russia "must withdraw all of its troops and military equipment from Ukraine, and respect Ukraine's independence, sovereignty, and territorial integrity within its internationally recognised borders", they said.

Putin on Friday annexed four territories in Ukraine controlled by his army at a ceremony in the Kremlin and urged Kyiv to lay down its arms and negotiate an end to seven months of fighting.

Putin was defiant during an address to Russia's political elites, telling the West that the land grab was irreversible and calling on Ukraine's emboldened army to give up and negotiate a surrender.

"I want to say this to the Kyiv regime and its masters in the West: People living in Luhansk, Donetsk, Kherson and Zaporizhzhia are becoming our citizens forever," Putin said.

"We call on the Kyiv regime to immediately stop fighting and stop all hostilities... and return to the negotiating table." (AFP)