MOSCOW (AFP) - Moscow on Thursday (April 12) said it would not accept the conclusions of the world's chemical arms watchdog on the poisoning of a former spy in England unless Russian experts could access the samples used.

"Russia won't take on faith any conclusion relating to the Skripal affair until such a time as Russian experts are allowed access to the samples mentioned (by the Organisation for the Prohibition of Chemical Weapons)," foreign ministry spokeswoman Maria Zakharova said.

The OPCW earlier said it had confirmed Britain's findings on the nerve agent used in the attack on Sergei Skripal and his daughter Yulia last month, which London said came from Russia.

"There is no information at all about how, from whom, in what conditions these samples were taken. This statement raises questions among Russian experts and, of course, requires additional detailed analysis," Zakharova said.

Moscow this month convened a meeting of the OPCW and made a bid for a joint investigation into the attempted murder, but the request was rejected.

Zakharova on Thursday repeated that Russia remained open for a joint investigation.

Britain blames Russia for the nerve agent attack on Sergei Skripal and his daughter Yulia on March 4, which has sparked an international diplomatic crisis.

Russia has vehemently denied the accusation and has requested access to the Skripals, who are both Russian citizens.