The United Kingdom on Thursday officially accused the Russian government of launching the destructive NotPetya attack, which had a significant financial impact on several major companies.

British Foreign Office Minister for Cyber Security Lord Tariq Ahmad said the June 2017 NotPetya attack was launched by the Russian military and it “showed a continued disregard for Ukrainian sovereignty.”

“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,” the official stated.

“The United Kingdom is identifying, pursuing and responding to malicious cyber activity regardless of where it originates, imposing costs on those who would seek to do us harm. We are committed to strengthening coordinated international efforts to uphold a free, open, peaceful and secure cyberspace,” he added.

The U.K. believes that while the NotPetya attack masqueraded as a criminal campaign, its true purpose was to cause disruption. The country’s National Cyber Security Center (NCSC) assessed that the Russian military was “almost certainly” responsible for the attack, which is the highest level of assessment.

The U.K. was also the first to officially accuse North Korea of launching the WannaCry attack. The United States, Canada, Japan, Australia and New Zealand followed suit several weeks later.

Last month, Britain's Defence Secretary Gavin Williamson accused Russia of spying on its critical infrastructure as part of a plan to create “total chaos” in the country.

While the U.S. has not made an official statement on the matter, confidential documents obtained by The Washington Post last month showed that the CIA had also concluded with “high confidence” that the Russian military was behind the NotPetya attack.

Cybersecurity firms and Ukraine, the country hit the hardest by NotPetya, linked the malware to other threats previously attributed to Russia.

The NotPetya malware outbreak affected tens of thousands of systems in more than 65 countries. Researchers initially believed NotPetya (also known as PetrWrap, exPetr, GoldenEye and Diskcoder.C) was a piece of ransomware, but a closer analysis revealed that it was actually a destructive wiper.

Rosneft, AP Moller-Maersk, Merck, FedEx, Mondelez International, Nuance Communications, Reckitt Benckiser, and Saint-Gobain reported losing hundreds of millions of dollars due to the attack.

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