France, Germany, Canada and US back Britain over Salisbury poisoning

In a joint statement, the other four countries said they backed Britain's assessment that Russian officers were behind a nerve agent attack on a former Russian spy and his daughter using Novichok after London charged two Russians in absentia.

"We have full confidence in the British assessment that the two suspects were officers from the Russian military intelligence service, also known as the GRU, and that this operation was almost certainly approved at a senior government level," the statement said, adding that the countries urged Russia to provide "full disclosure of its Novichok programme".

"Yesterday's announcement further strengthens our intent to continue to disrupt together the hostile activities of foreign intelligence networks on our territories, uphold the prohibition of chemical weapons, protect our citizens and defend ourselves from all forms of malign state activity directed against us and our societies."