The United Kingdom on Wednesday rejected Russia’s request to conduct a joint investigation into the nerve agent attack on a former Russian spy and his daughter, AFP reported. Moscow has called for an urgent United Nation Security Council meeting on Thursday to discuss the matter.

The Organisation for the Prohibition of Chemical Weapons met in the The Hague in the Netherlands where Russia’s request was rejected 32 votes to six.

“We will not agree to Russia’s demand to conduct a joint investigation into the attack in Salisbury because the UK – supported by many other countries – has assessed that it is highly likely that the Russian state is responsible for this attack,” John Foggo, British chemical arms expert, told the organisation’s governing executive council.

The United Kingdom and its allies, including the European Union and the North Atlantic Treaty Organisation, allege that Russia had a role in the nerve agent attack on former double agent Sergei Skripal and his daughter Yulia in Salisbury, England, on March 4. Russia has repeatedly denied any role in the incident. Skripal is still in a critical but stable condition, while his daughter’s condition is improving.

Moscow on Wednesday accused the UK and the United States of poisoning Skirpal to maintain Western unity against Russia, Bloomberg reported. The nerve agent attack was a “grotesque provocation” carried out by the US and British secret services, Sergei Naryshkin, director of Russia’s Foreign Intelligence Service, said. The U.K. must apologize to Russia, Kremlin spokesman Dmitry Peskov said.