The UK has assessed that the brazenness of the attacks that killed one Briton and sickened a former Russian spy and his daughter — including the amount of nerve agent used — point to approval by Russian President Vladimir Putin himself, two officials familiar with the matter told CNN. “It’s above the GRU leadership,” is as far as a British official would go when asked to confirm CNN’s reporting that Putin authorized the attack. “What that actually means, we can have a good guess.” British officials have warned allies that Russian intelligence agents risked killing thousands when they smuggled a perfume bottle packed with the deadly nerve agent Novichok into the UK to try to assassinate Sergei Skripal, a former Russian agent, according to two European intelligence officials. The poison, contained in a fake Nina Ricci perfume bottle, was enough to kill “thousands and thousands of people,” according to the intelligence officials, speaking anonymously in order to discuss sensitive briefings. “Just the amount on the head of a pin could kill,” one of the officials explained. “It could have been carried in by the Russians who carried out the operation,” on commercial aircraft, though it also could have been smuggled in a diplomatic pouch, they said. The sources provided more details behind the concern expressed by the British police officer leading the investigation into the attack in a BBC interview last week. There was “a significant amount” of Novichok contained in the bottle, Deputy Assistant Commissioner Dean Haydon told the BBC’s Panorama program, adding that “possibly into the thousands” of people could have been killed by it. Russia watchers, like former CIA officer John Sipher, who worked counterintelligence operations against Moscow, agree that Putin personally signed off on the operation because it had the potential to provoke a foreign policy backlash. “You don’t jump on a plane with enough doses to kill thousands … without your boss knowing about it,” Sipher said. “Because it was a GRU officer being targeted, even if they pulled it off perfectly, it would be blamed on Russia.” British officials wanted to make other European and allied intelligence agencies aware of both the scope of the threat, and the recklessness of the operation, with the Russian intelligence agents risking exposing civilians on their long journey carrying the toxic substance. The British government has publicly said that it has concluded that Russian military intelligence agents traveled to Salisbury, England, last March, and placed Novichok on the door handle of Skripal’s home, which ended up poisoning both him and his daughter, Julia. The Skripals ultimately recovered, but the perfume bottle used to transport the deadly substance ended up poisoning a couple living in Amesbury near Salisbury in June, when it was found and later given by Charlie Rowley to Dawn Sturgess. She died on July 8, a week after applying the substance to her wrists and falling ill. British investigators believe only one bottle was involved in both attacks, despite the claim by Rowley that he’d found a “sealed” perfume bottle, and given it to his partner, mother-of-three Sturgess. “The working assumption is that it was used and in a way resealed, and discarded — and that’s the perfume bottle being referred to in the Panorama report,” the British official said. The official dismissed Rowley’s claim that it was sealed like a new bottle of perfume, adding, “there’s sealed and then there’s wrapped, like wrapped with saran wrap.” “It’s above the GRU leadership,” the official said when asked to confirm CNN’s reporting that Putin authorized the attack. “What that actually means, we can have a good guess.” Top British security officials condemned Moscow in interviews last week. Britain’s new army chief called Russia a “far greater threat” than the Islamic State Group. Gen. Mark Carleton-Smith, Chief of the General Staff, told The Telegraph that Britain “cannot be complacent about the threat Russia poses.” “The Russians seek to exploit vulnerability and weakness wherever they detect it,” he added. While technically there were enough doses to kill “thousands” — a fact that shocked European security officials when they were briefed — there was no indication that the Russian agents wanted to kill that many people, a British official told CNN, speaking anonymously to discuss the ongoing investigation. “It’s more nuanced,” in that the main concern of British officials was the risk posed by traveling with that much nerve agent. The State Department did not immediately respond to requests for comment, and the British embassy in Washington declined to comment. Russia has consistently denied the British allegations, and Putin has personally dismissed the coverage of Skripal as western media hype. “I see that some of your colleagues are pushing the theory that Mr. Skripal is almost a human-rights activist” Putin said at an energy forum in Moscow this fall. “He’s just a spy. A traitor to the Motherland. There’s such a thing as a traitor to the Motherland. He’s one of them. He’s just a scumbag, that’s all.” The Russian embassy in Washington pointed to a November 23 statement by Alexander Shulgin, the permanent representative to the Organization for the Prohibition of Chemical Weapons: “We consider absolutely unacceptable the groundless accusations … pertaining to the alleged involvement of Russian nationals in the use of a nerve agent in Salisbury.” On the charge that Russia was more dangerous than ISIS, Russia’s Foreign Minister Sergey Lavrov has said, “Russia couldn’t ‘forbid anyone’ from “demonstrating their intellectual and political capabilities,” according to Russian embassy spokesman Nikolay Lakhonin who cited remarks reported by Sputnik, a Russian government-controlled news site.