The UN Security Council will hold an emergency meeting Wednesday at Britain's request to discuss the poisoning of a Russian former double agent in England.
Britain will brief council members during the open meeting at 1900 GMT on the nerve agent that left ex-spy Sergei Skripal and his daughter in critical condition, the British mission to the United Nations said.
Prime Minister Theresa May is due to outline Britain's response to the March 4 attack during a parliament session in London later Wednesday.
May has declared that it was "highly likely" that Russia was behind the attack, either directly or it had "lost control" of the nerve agent Novichok, developed by the Soviet Union.
Russia has denied any involvement.