US Ambassador to the United Nations Nikki Haley said Wednesday that a chemical attack on the country by Russia should not be ruled out.

“If we don’t take immediate concrete measures to address this now, Salisbury will not be the last place we see chemical weapons used,” said Haley. “They could be used here in New York or in cities of any country that sits on this council.”

She declared that the Trump administration “stands in absolute solidarity with Great Britain” following a nerve agent attack against a Russian double agent and his daughter in the English city of Salisbury last week.

In the strongest statement yet from the US administration on the affair, Haley said Washington shared the UK's assessment that the Russian state was behind the poisoning and demanded a firm international response.

“The United States believes that Russia is responsible for the attack on two people in the United Kingdom using a military-grade nerve agent,” Haley said in her remarks at a UN Security Council emergency session, blasting the Russian government for flouting international law.

The United Kingdom believes Russia was behind the attempted murders of Sergei Skripal and his daughter Yulia because the nerve agent used, Novichok, was developed in the Soviet Union and could not be replicated by non-state actors. London announced Wednesday it would expel 23 Russian diplomats after Moscow failed to meet a UK deadline to give a “credible response.”

Russia has dismissed the accusations as “fairy tales” and denied any involvement in the attack which landed the Skripals, along with a British police officer, in the hospital.

Moscow’s ambassador to the UN, Vassily Nebenzia, even suggested the UK might have been responsible for the attack in an attempt to smear Russia. “In the Russian Federation, no scientific research or development work under the title Novichok were carried out,” he told the Security Council.

“The most probable source origin this chemical are the countries which have since the end of the 90s been carrying... out intensive research on these kinds of weapons, including the UK.”

•Adapted from a CNN report.