The British government says it has evidence that North Korean hackers were behind the recent “WannaCry” cyber attack that crippled the country’s National Health Service.

“I think we should perhaps remember that this attack, we believe quite strongly, that this came from a foreign state,” U.K. Security Minister Ben Wallace said.

Asked which foreign state he believed was involved, Wallace said: “North Korea was the state we believe was involved in this worldwide attack on our systems.”

Malicious software called “WannaCry” targeted a number of businesses, government entities and the NHS earlier this year, blocking access to users’ systems until a sum of money was paid in a “ransomware” attack.

When asked if he was certain the attack came from North Korea, Wallace noted, “We can be sure as possible. I can’t obviously go into the detail of intelligence, but it is widely believed in the (intelligence) community and across a number of countries that North Korea had taken this role.”

Analyst comment: In 2011 the Obama administration decided that a cyber attack can be considered an “act of war,” but as of last year anyway, the government still had no concrete definition for a cyber act of war. Meanwhile, NATO, of which Britain is a long-standing member, has also decided that cyberspace is a warfare domain. That’s important because earlier this year NATO’s top European commander, British Adrian Bradshaw, the Deputy Supreme Allied Commander Europe, pushed the alliance to not only consider cyber attacks acts of war but also enough to trigger an Article 5 mutual defense response from all NATO members. While he was specifically talking about cyber attacks originating in Russia, certainly cyber attacks from other nations would apply should NATO decide they would trigger Article 5.

Why it’s on our radar: Information in this article helps satisfy Priority Intelligence Requirement 3: What are the latest indicators of a U.S.-North Korea conflict?  Each week in our Strategic Intelligence Summary, we gauge the likelihood and scope of conflict with Russia, China, North Korea, and in the Middle East, and track the latest developments in each region.  Subscribe here to receive our premium intelligence products prepared by Intelligence and special operations veterans.