Britain and Australia on Thursday accused Russian military intelligence of conducting a campaign of cyber attacks targeting political institutions, businesses, media and sport bodies around the world.
GRU, Britain said, was nearly certainly behind the BadRabbit and World Anti-Doping Agency attacks of 2017, the hack of the Democratic National Committee (DNC) in 2016 and the theft of emails from a United Kingdom -based TV station in 2015.
According to John Demers, the assistant attorney general for national security, members of the Russian military intelligence agency GRU engaged in a hacking conspiracy to obtain nonpublic health information about athletes and others in the anti-doping files of multiple sports organizations in the US and overseas.
"We are ready today to provide cyber support to our allies, I've seen enough of the evidence to say that the Dutch and the British are 100 per cent accurate in who they have attributed this to", Mattis said.
"The Russian military, and their intelligence arm "the GRU", is responsible for this pattern of malicious cyber activity", the Australian government said Thursday.
NATO Secretary General Jens Stoltenberg said the body backed Dutch and British authorities and said they must call Russian Federation out on "blatant attempts to undermine worldwide law and institutions".
The two leaders said Thursday they will "defend global institutions from those that seek do to them harm".
The 29 allies are discussing cybersecurity at talks in Brussels, with the U.S., Britain, Denmark and the Netherlands due to announce that they will provide offensive cyber-capabilities for use by North Atlantic Treaty Organisation.
The British ambassador to the Netherlands Peter Wilson also revealed how one of the agents allegedly attempted to disrupt the investigation into Malaysia Airlines Flight 17 (MH17), which was shot down in 2014.
He said: 'If anyone had any questions in their mind about Russian military involvement in the Salisbury attacks, this will put to rest those doubts because we have evidence of the Russian military launching a cyber-attack on the very worldwide organisation in the Netherlands set up to investigate those novichok attacks.
Maria Zakharova, a spokesperson for the Russian Ministry of Foreign Affairs, told a news briefing that the accusations were the product of someone with a "rich imagination".
They were caught trying hack into the Organisation for the Prohibition of Chemical Weapons' WiFi network by parking outside its headquarters with a cache of high-tech equipment inside the boot.
Russian President Vladimir Putin, a former KGB spy, said on Wednesday that Skripal, a GRU officer who betrayed dozens of agents to Britain's MI6 foreign spy service, was a "scumbag" who had betrayed Russia.
Well, we now know what she means.
The move will further strain relations between the two countries after Britain blamed Moscow for the nerve agent attack in Salisbury last March which left one person dead.
The Dutch government hopes that making the information public will make it harder for Russian Federation to carry out such covert operations in future.
They said the GRU military intelligence service could have only been conducting operations of such scale on Kremlin orders.
The hackers identified by the NCSC include an entity variously called "APT28", "Pawn Storm", "Sandworm", "Fancy Bear" and the "Sofacy Group", according to the British Foreign Office.
The UK's National Cyber Security Centre concluded that the GRU was behind the 2016 hacks of the US Democratic National Committee and the World Anti-Doping Agency. "This is the actions of a pariah state".
Williamson said: "This is not the actions of a great power".