The US and UK governments have publicly blamed Russia for a crippling cyber-attack last year that targeted Ukraine and spread around the world.

On Thursday, Sarah Sanders, the White House press secretary, said that the NotPetya ransomware attack in June 2017 “was part of the Kremlin’s ongoing effort to destabilise Ukraine and demonstrates ever more clearly Russia’s involvement in the ongoing conflict.”

She added: “This was also a reckless and indiscriminate cyber-attack that will be met with international consequences.” Sanders said it had caused billions of dollars of damage.

The statement came after the British defence secretary, Gavin Williamson, accused the Russian government of “undermining democracy” with the attack, which primarily targeted Ukraine’s financial, energy and government sectors before it spread across the world.

The two governments’ unusual public accusation echoed the conclusions already reached by many private sector cyber security experts.

Ukraine has been in conflict with Kremlin-backed separatists since Russia annexed Crimea in 2014.

Williamson said: “We have entered a new era of warfare, witnessing a destructive and deadly mix of conventional military might and malicious cyber-attacks.

“Russia is ripping up the rulebook by undermining democracy, wrecking livelihoods by targeting critical infrastructure and weaponising information ... We must be primed and ready to tackle these stark and intensifying threats.”

Russia has denied responsibility for the attack, which is estimated to have cost companies more than $1.2bn (£850m). It claimed that Russian businesses were among those with systems affected.

The foreign minister, Lord Ahmad, said the UK’s decision to identify the Kremlin as responsible showed that the government would not tolerate malicious cyber activity.

“The UK government judges that the Russian government, specifically the Russian military, was responsible for the destructive NotPetya cyber-attack of June 2017 ... The Kremlin has positioned Russia in direct opposition to the west, yet it doesn’t have to be that way.

“We call upon Russia to be the responsible member of the international community it claims to be, rather then secretly trying to undermine it ... We are committed to strengthening coordinated international efforts to uphold a free, open, peaceful and secure cyberspace.”



In November, Theresa May accused Vladimir Putin of attempting to “sow discord” in the west by spreading misinformation.

MPs have asked social media companies to look into claims that Russian hackers tried to influence the outcome of the EU referendum.

YouTube and Facebook said inquiries had found no evidence of this.