A coat of arms is seen on the wall of the consular section of Russia's embassy in London, Britain, March 15, 2018. REUTERS/Hannah McKay

AMSTERDAM (Reuters) - Russia must cooperate with the world’s chemical weapons body and disclose a “Novichok” nerve agent program after a former spy was attacked with military-grade toxin in an English city, the European Union said on Thursday.

“We support the call for a full and complete disclosure by the Russian Federation,” Bulgaria’s envoy to the Organisation for the Prohibition of Chemical Weapons in The Hague, Krassimir Kostov, told members of the OPCW’s executive council.

“We call on the Russian Federation to respond swiftly to the British government’s legitimate questions and to co-operate with the OPCW,” said Kostov, who made the comments on behalf of the EU.

The EU’s appeal to Russia came after Britain, the United States, Germany and France jointly called on Russia to explain the military-grade nerve toxin attack in England which they said threatened Western security.

Former Russian spy Sergei Skripal and his daughter Yulia are in critical condition after being poisoned in the southern English city of Salisbury on March 4.

Britain has asked the OPCW to independently verify the findings of its bio-chemical weapons laboratory, Porton Down, that the nerve agent was the powerful Soviet-era toxin.

Russia declared roughly 40,000 tonnes of chemical weapons to the OPCW in the 1990s. The agency said in October that Moscow had completed destruction of the stockpile. It did not declare Novichok.