Russia has again insisted it had nothing to do with the chemical nerve agent attack on a former double agent and his daughter in the UK.
Sergei Skripal and his daughter Yulia remain in critical condition in a British hospital.
The UN Security Council held an urgent meeting to discuss the attack this evening.
Opening the meeting, Britain’s deputy UN ambassador Jonathan Allen said hundreds of his countrymen had potentially been exposed to the agent.
He said the pair were poisoned with ‘Novichok’ - which he insisted is a weapon that cannot be manufactured without the use of the highest grade state laboratories.
He called it a despicable act:
“This was no common crime,” he said. “It was an unlawful use of force.”
“A violation of Article Two of the United Nations charter – the basis of the international legal order.”
He noted that Russia had failed to respond to Britain’s ultimatum for an explanation as to how the agent could have fallen into anyone else’s hands – and noted that Novichok was not among the list of agents that Russia declared as destroyed after it signed the Chemical Weapons Convention.
It comes after the British Prime Minister blamed Russia for the attack and announced the expulsion of 23 Russian diplomats as part of a range of measures in response.
It is the biggest expulsion since the Cold War.
At the Security Council meeting in New York however, Russian representative Vasily Nebenzya however accused Mrs May of making completely irresponsible statements" and "threats to a sovereign state."
Russia has said it will not respond to Britain's ultimatum until it recieves samples of the chemical used in the attack.
Mr Nebenzya said an "historical atmosphere" was being created by the accusations - adding that Russia demanded proof that traces of Novichok had been found.
He also suggested that several other countries were capable of creating the agent.
He said Britain’s ultimatum would be ignored adding that it was “null and void.”
“We expect that the UK will act in strict adherence with the Convention of Chemical Weapons and other international instruments including the European Convention on Legal Assistance in Chemical Matters and will provide the samples of substances that the UK investigation is referring to for a joint investigation, since you are saying they are Russian in origin,” he said.
“This is not optional. This is a mandatory requirement under the convention.
“We stand ready for such an investigation.
“We have nothing to fear; we have nothing to hide.”
US Ambassador to the UN Nikki Haley speaks during the emergency Security Council meeting, 14-03-2018. Image: Mary Altaffer/AP/Press Association Images
The US Ambassador Nikki Haley said the US stands in “absolute solidarity with Great Britain”
“The United State believes that Russia is responsible for the attack on two people in the United Kingdom using a military grade nerve agent.
“Dozens of civilians and first responders were also exposed.”
She warned that the Security Council was faced with a “defining moment” – adding that its credibility will not survive if it fails to take action.
"If we don’t take immediate, concrete measures to address this now; Salisbury will not be the last place we see chemical weapons used,” she said.
“They could be used here in New York; or in cities of any country that sits on this council.”
She said that as a permanent member of the Security Council, Russia has a responsibility to uphold the UN charter, peace and security – adding that it must account for its actions.
France also offered its full support to the UK with its permanent representative warning that “what is at stake is extremely serious.”
"There can be no ambiguity in regard to our position on this,” he said. “We have full confidence in the British investigation."
Both Sweden and Poland both also expressed their full solidarity with the UK.
China called for the crisis to be handled through the “proper channels” while Peru said the investigation must follow due process through the Organisation for the Prohibition of Chemical Weapons.