Liz Truss has accused Vladimir Putin of breaking international law as the Russian president plans to formally annex four regions of Ukraine.
Moscow is preparing to annex the four regions of Luhansk, Donetsk, Kherson and Zaporizhzhia from Russia following internationally criticized referendum votes as part of its invasion of Ukraine, with the Kremlin expected to formally end the process on Friday.
In a statement, the prime minister said: “Vladimir Putin has once again acted in violation of international law with a clear disregard for the lives of the Ukrainian people he claims to represent.
“The UK will never ignore the sovereign will of these people and we will never accept the regions of Donetsk, Luhansk, Kherson and Zaporizhzhia as anything other than Ukrainian territory.
“Putin cannot be allowed to alter international borders through brute force. We will make sure he loses this illegal war.
The latest move by Russia, currently under pressure after a series of Ukrainian successes, has drawn global condemnation and been rejected by Ukrainian President Volodymyr Zelensky.
James Cleverly, the foreign secretary, said the UK does not recognize Putin’s “sham referendums”.
“They are illegal, they are illegitimate. Territorial integrity of Ukraine must be respected,” he tweeted.
The UN Security Council has also scheduled a vote on a resolution that would condemn Russia for its “so-called illegal referendums” in Ukraine’s four regions, declaring them “invalid.”
Earlier, a Russian attack on a humanitarian convoy in the city of Zaporizhzhia killed at least 23 people and wounded 28, Ukrainian authorities said.
Since becoming Prime Minister, Ms Truss has pledged to follow Boris Johnson’s lead in providing much-needed support to Ukraine.
In a call with Zelensky this week, he stressed that the UK would not accept annexations.