Russian Foreign Minister Sergei Lavrov said on Friday a report by the Organization for the Prohibition of Chemical Weapons (OPCW) did not confirm the origin of the poison used against a former Russian spy, accusing his British counterpart of distorting the findings.
He said the report only confirmed the composition of the substance and that Britain's claim that the OPCW report confirms its position on the case of Sergei Skripal and his daughter Yulia is overstated.
"Already politicians like Boris Johnson are once again trying to distort the truth and announce that the OPCW statement supports Britain's conclusions without exception," Lavrov said.
On Thursday, OPCW confirmed Britain's finding that Skripal and his daughter were poisoned with a nerve agent in the English city of Salisbury on March 4.
Investigators from the watchdog said the nerve agent was "of high purity."
Britain says that means only a state with a sophisticated laboratory could have manufactured it.
The watchdog's report does not say who was responsible for the attack, since that was outside the scope of its mission. The OPCW's job was to identify the poison, not to trace its origins or assign blame.
Moscow on Thursday said it feared the UK had forcibly detained Yulia.
"We have every reason to believe this could be a question of the deliberate, forcible detention of a Russian citizen or possibly their coercion into a staged announcement," foreign ministry spokeswoman Maria Zakharova said.
The woman was discharged from hospital on Monday, more than a month after the nerve agent attack.
While her whereabouts are unknown, Skripal said she is being supported by police officers who are keeping her informed of their high-profile investigation.
On Wednesday she said she did not currently wish to take up an offer of consular assistance from the Russian embassy, according to a note released by London's Metropolitan Police.
