Russia on Saturday denied claims that the substance used to poison former double agent Sergei Skripal and his daughter Yulia in England was developed in the country or the Soviet Union, Reuters reported. Russian Foreign Minister Sergei Lavrov said it had evidence to prove that the poison could have been created in the United States, Britain or several of the North Atlantic Treaty Organisation member states.

Lavrov said evidence from an analysis conducted in a Swiss laboratory of the substance used in the poisoning indicated that it had traces of the BZ agent. On April 12, the Organisation for the Prohibition of Chemical Weapons – an international chemical weapons watchdog – confirmed the United Kingdom’s findings on the nerve agent used to poison the former Russian spy. While the agency did not name the nerve agent as Russia-made novichok, it said it agreed with the UK’s analysis.

The Russian foreign minister was speaking at an assembly of the Council on Foreign and Defence Policy. “This formulation was in the inventory of the United States, Britain and other NATO states,” Lavrov quoted the laboratory report as saying.

On March 4, the father and daughter were found unconscious on a park bench outside a shopping centre in Salisbury. The poisoning has led to a major diplomatic controversy globally. The UK and its allies, including the European Union and the North Atlantic Treaty Organisation, have accused Moscow of involvement in the incident and expelled 23 Russian diplomats from their territory. Maintaining innocence, Russia has responded by expelling an equal number of British diplomats.