The UK's new foreign secretary will condemn Moscow’s atrocities in Ukraine when he meets his Russian counterpart for the first time.
James Cleverly will face Sergey Lavrov on Thursday during a special meeting of the UN Security Council, where foreign ministers are scheduled to discuss the war.
World leaders and senior diplomats from around the globe have gathered at the UN General Assembly in New York this week, with Mr Cleverly attending as part of a UK delegation headed by Prime Minister Liz Truss. This is his first overseas trip since taking up his new role.
Global affairs continue to be overshadowed by the Ukraine conflict, which threatened to spiral into a nuclear crisis after Russian President Vladimir Putin said that his country would use “all the means at our disposal” to protect itself.
In a speech on Wednesday, the Russian president also announced a partial military mobilisation as the Kremlin attempts to regain ground in the face of a counter-offensive by Ukraine’s forces.
At the Security Council meeting, Mr Cleverly will commit to working with allies on holding Russia accountable and seeking justice for victims.
“Ukrainians’ resilience and spirit of defiance in defence of their country continues to inspire all free people and nations,” he is expected to say.
“But every day, the devastating consequences of Russia’s invasion become more clear and evidence of Russian atrocities continues to mount.
“We can and must make clear to President Putin that his attacks on the sovereign will of the Ukrainian people — so clearly expressed as they fight for their homes — must stop, his assaults on the UN Charter and international norms that protect us will not be tolerated, and that he must withdraw from Ukraine to enable a return to regional and global stability.”
The foreign secretary will also argue that Moscow plans to fix the results of referendums due to be held in Russian-controlled regions of eastern and southern Ukraine on becoming part of Russia.
Russia is outnumbered on the Security Council, but wields a veto.
Later on Thursday, Mr Cleverly will join a meeting focused on accountability for war crimes in Ukraine.
Mr Cleverly and US Secretary of State Antony Blinken both stressed unwavering support to Kyiv and to “maintaining unity with partners to ensure Putin fails in his illegal war” when they met at the UN gathering on Tuesday, a readout of the encounter said.
The British foreign secretary also had a meeting with Ukrainian Foreign Minister Dmytro Kuleba.
In her summit speech, Ms Truss pledged that the UK under her leadership would work with allies to counter authoritarianism and champion freedom, sovereignty and democracy.
The prime minister met Ukrainian first lady Olena Zelenska and Prime Minister Denys Shmyal during a tour of an exhibition entitled “Russian Warcrimes” at the Ukrainian Institute of America on Tuesday.