Britain is accusing Russian military intelligence of being behind a host of recent cyberattacks seeking to undermine critical Western institutions from sports and transportation authorities to election processes.
A British national security report released late on October 3 concludes that the Russian military intelligence agency, or GRU, is "a pernicious cyber-aggressor" that has used a network of hackers to spread discord and confusion across the world.
The Russian Foreign Ministry on October 4 described the accusations as "fantasy," as British Defense Secretary Gavin Williamson condemned Russia as a "pariah state" whose "reckless and indiscriminate" attacks had left it isolated in the international community.
The GRU, the British report said, was almost certainly behind the "BadRabbit" ransomware attack last year that targeted a Ukrainian international airport and Russian media outlets, as well as the hacking of the World Anti-Doping Agency in Switzerland.
It also concluded that the GRU was behind hacks and leaks of U.S. Democratic National Committee e-mails that embarrassed President Donald Trump's opponent Hillary Clinton in the weeks before the 2016 election, among other high-profile and damaging attacks.
"The GRU's actions are reckless and indiscriminate: they try to undermine and interfere in elections" in a clear assault on Western democracy, British Foreign Secretary Jeremy Hunt said in releasing the report.
But some of the GRU's cyberattacks "serve no legitimate national security interest, instead impacting the ability of people around the world to go about their daily lives free from interference, and even their ability to enjoy sport," Hunt said.
"Our message is clear: together with our allies, we will expose and respond to the GRU's attempts to undermine international stability," he said.
The British report said the GRU had associated itself with a host of hackers involved in high-profile attacks, known by such names as APT 28, Fancy Bear, Sofacy, Pawnstorm, Sednit, CyberCaliphate, Cyber Berkut, Voodoo Bear, and BlackEnergy Actors.
"This pattern of behavior demonstrates their desire to operate without regard to international law or established norms and to do so with a feeling of impunity and without consequences," Hunt said.
Russian Foreign Ministry spokeswoman Maria Zakharova rejected the British allegations, saying, "They mixed up everything in one bottle.”
"This is just a diabolical perfume blend. The imagination of our U.K. colleagues is truly boundless," she added.
The United States has already accused the GRU of being behind cyberattacks before the 2016 presidential election and has sanctioned GRU officers -- including its chief, Igor Korobov -- for their alleged actions.
The U.S. Treasury said in March that the GRU "knowingly engages in significant activities that undermine cybersecurity on behalf of the Russian government."
Though less well-known than the Soviet Union's KGB spy agency, the GRU played a major role in some of the biggest events of the past century, from the Cuban missile crisis in the 1960s to the annexation of Ukraine's Crimean Peninsula in 2014.
It has agents across the globe and answers directly to the chief of the Russian General Staff and the defense minister. The GRU does not comment publicly on its actions. Its structure, staff numbers, and financing are Russian state secrets.
British Prime Minister Theresa May has said GRU officers were behind an attempt to kill former Russian double agent Sergei Skripal and his daughter with a nerve agent in the English city of Salisbury in March. Russia has denied the charges.
After the Skripal poisoning, the West agreed with Britain's assessment that the GRU was to blame and launched the biggest expulsion of Russian spies working under diplomatic cover since the height of the Cold War.
Russian President Vladimir Putin, himself a former KGB spy, said on October 3 that Skripal, a GRU officer who betrayed dozens of agents to Britain's MI6 foreign spy service, was a "scumbag" who had betrayed his country.