Four GRU officers entered the Netherlands at Amsterdam's Schiphol Airport on April 10 (Picture: Dutch Ministry of Defence Handout)
Russia's military intelligence service has been accused of trying to hack the global chemical weapons watchdog which is investigating the Salisbury nerve agent attack.
Officials in the Netherlands, where the Organisation for the Prohibition of Chemical Weapons (OPCW) is based, said four Russians had been expelled after the alleged cyber strike.
British intelligence helped thwart the operation which was launched in April, a month after the Salisbury Novichok poisoning which targeted Russian spy Sergei Skripal.
Details were revealed on Thursday after the UK Government accused the GRU of a wave of other cyber attacks across the globe.
Prime Minister Theresa May said the operation "further shone a light on the unacceptable cyber activities" of the GRU and demonstrated its "disregard for the global values and rules that keep us safe".
A team of four GRU officers travelling on official Russian passports entered the Netherlands on April 10.
On April 13 they allegedly parked a car carrying specialist hacking equipment outside the headquarters of the OPCW in The Hague.
At that point, Dutch counter-terrorism officers intervened to disrupt the operation and the four GRU officers were ordered to leave the country.
Defence Secretary Gavin Williamson said he welcomes the Dutch operation, and that the UK "stands solidly" with them.
"Unfortunately, the case highlighted by the Dutch was not an isolated act. Earlier today, the British Government exposed a campaign of indiscriminate and reckless cyber attacks targeting political institutions, businesses, media and sport," he said.
"We identified that these attacks were, in fact, the GRU.
"They served no legitimate national security interest. Instead they targeted people going about their daily lives; and international organisations, like the OPCW, whose work represents the global community's shared values.
"All these cases are further examples of a pattern of reckless behaviour.
"It is the Russian state that bears the grave responsibility for actions of the GRU."
The attempt on the OPCW headquarters followed unsuccessful "spearphishing" attacks by the GRU on the UK Foreign Office and on the defence laboratories at Porton Down, which was also investigating the Salisbury attack.
The OPCW has confirmed the toxic chemical that killed Dawn Sturgess in Amesbury was the same nerve agent as that which poisoned Sergei and Yulia Skripal three months earlier.
UK authorities believe two Russians, going by the names Alexander Petrov and Ruslan Boshirov, smeared the highly toxic Novichok on a door handle at the Wiltshire home of Mr Skripal on March 4.
The attack left Mr Skripal and his daughter Yulia critically ill, and Ms Sturgess, 44, who was later exposed to the same nerve agent, died in July.
Conservative MP Tom Tugendhat, chairman of the UK's Commons Foreign Affairs Committee, tweeted: "The catalogue of evidence shows why the Dutch are excellent partners and that the decades of theft have stripped Russia's intelligence of the skills they once had.
"Putin's corrupt greed has turned the GRU into an amateurish bunch of jokers."