Earlier this year, a nasty piece of ransomware dubbed “WannaCry” began infecting computers all across the globe. Based off of an NSA exploit, WannaCry specifically targeted Windows machines and prevented users from accessing their files unless they agreed to make a $300 payment in Bitcoin. Compounding matters is that the ransom amount was designed to increase if users didn’t make a prompt payment.

When all was said and done, WannaCry left a massive amount of damage in its wake. In just a few days, WannaCry managed to infect upwards of 300,000 machines in nearly 150 countries. What’s more, it even impacted and wreaked havoc on computer systems at sensitive locations like hospitals. Now, seven months later, we finally know who was behind the widespread ransomware campaign: North Korea.

Late on Monday, the Trump administration officially cast blame for WannaCry on North Korea. In an op-ed published in The Wall Street Journal, Homeland Security Advisor Tom Bessert wrote that North Korea was “directly responsible” for the malware that “cost billions.”

While this isn’t the first report we’ve seen implicating North Korea, this is the first time the U.S. Government, in an official capacity, has chimed in on the matter.

“After careful investigation, the U.S. today publicly attributes the massive “WannaCry” cyberattack to North Korea,” Bessert writes. “We do not make this allegation lightly. It is based on evidence. We are not alone with our findings, either. Other governments and private companies agree. The United Kingdom attributes the attack to North Korea, and Microsoft traced the attack to cyber affiliates of the North Korean government.”

“North Korea has acted especially badly, largely unchecked, for more than a decade, and its malicious behavior is growing more egregious,” Bessert later added. “WannaCry was indiscriminately reckless.”

Looking ahead, Bessert writes that the U.S. will take steps to curtail North Korea’s “ability to mount attacks, cyber or otherwise.”

In light of Bessert’s op-ed, a follow-up statement from the White House is expected to be released sometime on Tuesday.