Britain's defense chief has said that a Russian "attack" led to the death of a mother of three who was exposed to the same nerve agent that put former spy Sergei Skripal and his daughter in the hospital, while the Kremlin said it would be "absurd" to blame Moscow.
The conflicting comments on July 9 came as more details emerged about the death of Dawn Sturgess, 44, in southern England a day earlier following what police say was an unexplained exposure to the nerve agent Novichok.
"The simple reality is that Russia has committed an attack on British soil which has seen the death of a British citizen," Defense Secretary Gavin Williamson said when asked in parliament about the threat facing people in Britain.
"That is something that I think the world will unite with us in actually condemning," Williamson said.
He spoke hours after Russian President Vladimir Putin's spokesman, Dmitry Peskov, said that the Kremlin believes "it would be quite absurd" to blame Russia for the poisoning of Sturgess.
And Russia's Foreign Ministry posted a sneering comment to Twitter, accusing British authorities of always seeking to blame Moscow.
"Could you perhaps come up with something new? A proper and careful investigation for instance?" the ministry said in its post directed at Williamson.
Peskov's remarks were in line with repeated Kremlin denials of Russian involvement in the March poisoning of Sergei and Yulia Skripal with Novichok in the southern English city of Salisbury.
Britain has blamed Putin's government for the poisoning of the Skripals, which triggered a diplomatic row in which Britain and its allies expelled more than 150 Russian diplomats.
British police said they believe Sturgess and her partner, Charlie Rowley, must have handled a container of the substance and been exposed to a "high dose."
British counterterrorism chief Neil Basu said on July 9 that the death of Sturgess shows that she and Rowley were exposed to a large quantity of Novichok, a military-grade nerve agent produced in the Soviet Union during the Cold War.
Basu said the working theory is that their exposure was linked to the poisoning of the Skripals, who have recovered after being exposed to Novichok in early March.
Britain has called on Russia to answer questions about where the nerve agent came from. Peskov tried to turn the tables, saying Russia is "deeply worried by the continuing presence of these poisonous substances on British territory."
This poses "a danger not only for the British, but for other Europeans," he said.
British authorities say Sturgess and Rowley, 45, were found unconscious on June 30 at a house in Amesbury, less than 20 kilometers from Salisbury.
The death of Sturgess is now being investigated as a murder.
"Her death has only served to strengthen the resolve of the investigations team," Basu said, adding that a priority for police is to find any container that may be the source of the Novichok.
More than 100 police are trying to search all areas where Sturgess and Rowley had been before they became ill. The search is focused on their homes and a park in Salisbury.
He said no one else in the area has shown any sign of Novichok poisoning.
Prime Minister Theresa May said on July 8 that she was "appalled and shocked" by the death of Sturgess, and a spokesman for May said that Britain's interior minister will chair a meeting of the government's emergency committee on July 9.
Basu called the death of Sturgess "shocking and tragic news."
"This terrible news has only served to strengthen our resolve to identify and bring to justice the person or persons responsible for what I can only describe as an outrageous, reckless, and barbaric act," Basu said on July 8.
In the immediate aftermath of Sturgess’s death, Russian officials and state media appear to have refrained from the snark and sarcasm that permeated their public responses to British accusations of Russian involvement in the Skripals' poisoning.
Russian state television reports on July 9 nonetheless continued to cast doubt on the British investigation.
One senior Russian official suggested Sturgess's death was part of an effort to fan tensions between Moscow and Washington ahead of next week’s summit between Putin and U.S. President Donald Trump in Helsinki.
"The circumstances in the Amesbury situation are troubling: recently, such cases emerge ahead of important events," Aleksandr Shulgin, Russia’s envoy to the Organization for the Prohibition of Chemical Weapons, was quoted by the Izvestia newspaper as saying in an interview published July 9.
"Right now, the final stage of the 2018 World Cup [hosted by Russia] and the summit between Russia and the United States in Helsinki are coming. It's difficult to shake the feeling that all of this was planned and deliberately thrown out there to inflame world events and damage Russia's authority and its relations with other countries," Shulgin added.
Sergei Zheleznyak, a member of the ruling United Russia party, also accused Britain of trying to sully the July 16 summit.
Britain "understands that direct dialogue between the two superpowers is capable of reducing the level of confrontation, gradually raising the level of trust between our countries, and destroying the lies fabricated against Russia," Zheleznyak said in July 9 comments released by his party.
"That’s not advantageous to Britain’s leadership, and so as we get closer to the talks in Helsinki, we can expect new 'sensational' investigations from British authorities, in which a 'Russian' link must undoubtedly be identified," added Zheleznyak, a member of the foreign affairs committee in the lower house of parliament.
Following the poisoning of the Skripals, the Russian government floated an array of unsubstantiated theories about the their poisoning in what Britain has criticized as a cynical effort by Moscow to muddy the waters surrounding the investigation.
In a post to Facebook July 9, Foreign Ministry spokewoman Maria Zakharova linked the poisoning to the resignation of Foreign Secretary Boris Johnson, who announced he was leaving his post just hours before Williamson spoke. And she suggested the British government was conducting scientific experiments using Novichok.
"It was one thing to carry out experiments on the Skripals, who were Russians, but on their own citizens is a different thing," she wrote. "They have to answer to their own people, not just make up stories for NATO."