As international chemical weapons traveled to Great Britain this week to study samples of the nerve agent used to poison Russian ex-spy Sergei Skripal and his daughter, Yulia, Moscow decided to go on the offensive and accuse London of orchestrating the apparent assassination attempt and stockpiling the toxin in secret laboratories.

On Tuesday, diplomats from more than 40 states gathered at the Russian Ministry of Foreign Affairs in Moscow to hear a statement on the poisoning from its top officials and members of the Defense Ministry. Five Russian officials blamed Great Britain for making up false accusations against Russia, for hiding and testing its own secret chemical weapons, for lying to the world, and for orchestrating the poisoning of the two Russian citizens in Salisbury on March 4th.

As the popular saying goes, the best defense is offense.

The Skripal poisoning has triggered a diplomatic crisis between Russia and Britain; both states have decided to expel diplomats. Skripal and his daughter remain hospitalized in intensive care at Salisbury hospital. UK Prime Minister Theresa May has blamed Russia for the poisoning, with British authorities insisting that the nerve agent—“novichok”—was made at only one site in Russia.

Meanwhile, for weeks, Russian television channels have been blaming London for creating a diplomatic crises right before Russia’s Presidential Election. They’ve offered different explanations for the supposedly manufactured crisis to TV viewers—from the British government trying to distract its own electorate from various issues around Brexit, to the British military looking for excuses to obtain big budgets and develop chemical weapons.

At the meeting on Tuesday, Vladimir Yermakov, Director of Foreign Ministry Department for Nonproliferation and Arms Control, urged the diplomats to have a “highly professional and non-politicized discussion” even as he insisted that British authorities were to blame for failing to prevent a “terrorist” attack on Russian citizens on its soil. Smiling a thin smile, he added that Britain’s “hysterical accusations” against Russia had no ground and that the poisoning was unacceptable to the Kremlin.

“Logic suggests that there are only two possible things. Either the British authorities are not able to provide protection from such a, let’s say, terrorist attack on their soil, or they—whether directly or indirectly, I am not accusing anyone—have orchestrated an attack on a Russian citizen,” Yermakov said.

Yermakov also hinted darkly that “all this dirty hustle around Salisbury might have been orchestrated from overseas,” a veiled reference to Washington. Several times during the meeting, the official shamed foreign diplomats for daring to suspect Moscow was involved in the poisoning.

Another official at the meeting, General Igor Kirillov, invited the diplomats to take a broader look at Skripal’s case and mentioned Britain’s new defense center for chemical weapons at Porton Down military research base, not far from Salisbury. Kirillov pointed out that Great Britain was planning to spend $68 million on the new center. “At the time when all countries of the world are making efforts to destroy chemical weapons, Great Britain is developing a laboratory in Porton Down. They continue to experiment, exposing their own people to danger,” Kirillov said, insinuating that the poisoning could be traced back to Porton Down.

Earlier this week Russia’s Permanent Representative to the EU Vladimir Chizhov also hinted at a conspiracy theory around Porton Down, which lies around 7 miles from Salisbury. Chizhov stressed that Moscow had no bad blood with Skripal, a former intelligence officer for Russia.

Even as Moscow points fingers at Britain, an international community of experts—including the Organization for the Prohibition of Chemical Weapons, or OPCW, is studying the origins of the nerve agent. “Look, there is no doubt that “novichok” poisonous substance has been made in Russia. But it looks like the Kremlin gave a command to our diplomats and the Defense Ministry to deny everything—so they do,” Igor Bunin, a Chair at the Center for Political Technologies, told The Daily Beast on Tuesday. “Three scientists have described how they were making novichok, we’ve heard many descriptive details of that laboratory to believe that it once existed.”

These three Russian scientists—Vil Mirzoyanov, Vladimir Uglev, and Leonid Rink—confirmed that a branch of the State Scientific-Research Institute for Organic Chemistry and Technology (GOSNIIOKHT), based in Saratov region developed a group of substances referred to as “novichok” in 1970’s and 1980’s. One of the scientist, Vladimir Uglev, told The Bell: “Sometimes (it was made) in pilot production, but also using the laboratory table and equipment. Doses generally ranged from 20 grams to several kilos.”

The scientist explained that, together with the laboratory’s supervisor Pyotr Kirpichev, he had stored the poisonous substance in metal boxes sealed tight. “I don’t know anything else about what then happened to the doses beyond where they were stored,” Uglev added.

In 2008, exiled scientist Mirzayanov published the formula for the nerve agent “novichok” in a book called State Secrets: Insider's Chronicle Of The Russian Chemical Weapons Program Secrets.

Last week, Mirzayanov, who now lives in New Jersey, gave an interview to Current Time, the online TV of Radio Free Europe. The scientist guessed that not only Russia but other countries could have “novichok,” too.  “The British could certainly have synthesized it on the basis of the formulas that I published in my book,” Mirzayanov said in the interview. “Many countries could have had test samples—but production was only refined in the U.S.S.R. and Russia.”