A global chemical-weapons watchdog says samples taken from Russian opposition figure Aleksei Navalny have confirmed the presence of a chemical agent from the banned Novichok group, triggering renewed international calls for Russian authorities to investigate the matter.
Biomarkers in Navalny's blood and urine had "similar structural characteristics as the toxic chemicals belonging" to the Novichok group, the Organization for the Prohibition of Chemical Weapons(OPCW)said in a statement on October 6.
"These results constitute a matter of grave concern," said OPCW Director-General Fernando Arias, who called on members to uphold the international treaty banning the use of chemical weapons.
The findings confirm results released by Germany, where Navalny was treated after falling seriously ill on a flight from Siberia to Moscow on August 20.
German authorities asked The Hague-based OPCW to take samples from Navalny and test them after German doctors concluded he had been poisoned with a Novichok-like nerve agent.
Their findings were independently confirmed by laboratories in France and Sweden, sparking international condemnation and calls for sanctions against Moscow over the case.
Russia has denied any involvement and resisted international pressure to launch a criminal investigation.
Leonid Slutsky, chairman of the Foreign Affairs Committee in the State Duma, the lower house of Russia's parliament, said the conclusions of the OPCW experts were "politically biased."
The OPCW's announcement "once again confirms unequivocally that Aleksei Navalny was the victim of an attack with a chemical nerve agent from the Novichok group," German government spokesman Steffen Seibert said in a statement.
Seibert reiterated Germany's call on Russia to fully investigate and explain what happened to Navalny and said Berlin would in the coming days discuss the next steps with the OPCW and "the EU partners."
"Any use of chemical weapons is serious and cannot be without consequences," he added.
A joint statement from 44 OPCW member countries, tweeted by the British delegation to the organization, called on Moscow to "investigate and to disclose, in a swift and transparent manner, the circumstances of this chemical weapons attack."
British Foreign Secretary Dominic Raab said his country will consider what further action to take against Russia over the case.
London hasn't yet attributed the poisoning to Russia’s FSB security service or the Russian state, Raab told a parliamentary committee, but he added that there is “an incredibly strong case for Moscow to answer."
In an interview on October 5, Navalny again blamed President Vladimir Putin for the poisoning incident and confirmed he plans to return to Russia after he fully recovers in Germany.
The 44-year-old also said that his health continues to improve since being discharged on September 22 from the Berlin hospital where he was being treated for 32 days, including 24 days in an intensive-care unit.
The longtime Kremlin critic and anti-corruption campaigner spent nearly three weeks in an induced coma in Berlin and the Siberian city of Omsk, where Russian doctors said they found no trace of any poisoning.
Moscow denied that Russia or the Soviet Union had ever developed or made the family of nerve agents at the center of the international findings, Novichok, despite decades of overwhelming evidence to the contrary.
Chemical agents such as those in the Novichok group are banned under the Chemical Weapons Convention of 1997 and have never been shown to have been used on the battlefield.
A British investigation determined that they were used in the 2018 poisoning of former Soviet intelligence officer Sergei Skripal and his daughter by Russian agents in Salisbury, England.
The British government expelled 23 Russian diplomats after Moscow refused to cooperate with an investigation into the Skripal poisoning. The United States and other European states expelled dozens of Russian diplomats in a coordinated response.