The Trump administration has blamed North Korea for spreading the so-called "WannaCry" cyberattack that impaired hospitals, banks and other companies worldwide earlier this year.
"The attack was widespread and cost billions, and North Korea is directly responsible," the White House homeland security adviser Tom Bossert wrote in an opinion piece published on Monday online by the Wall Street Journal.
Bossert said anyone who harmed the United States would be held accountable, adding it would continue to pursue a "maximum pressure strategy."
"North Korea has acted especially badly, largely unchecked, for more than a decade, and its malicious behavior is growing more egregious," Bossert wrote.
A senior administration official who spoke on condition of anonymity said that “WannaCry was indiscriminately reckless,” adding the White House was expected to follow up on Tuesday with a more formal statement blaming Pyongyang.
The official explained that the US government has assessed with a "very high level of confidence" that a hacking entity known as Lazarus Group, which works on behalf of the North Korean government, carried out the WannaCry attack.
Washington's public announcement does not include any indictments or name specific individuals, the administration official said, adding the shaming was designed to hold Pyongyang accountable for its actions and "erode and undercut their ability to launch attacks."
The accusation comes as worries mount about North Korea's hacking capabilities and its nuclear weapons program.
UK also blames N Korea for ransomware incident
Britain has also joined the United States in blaming Pyongyang for the ransomware incident saying North Korea was behind the “WannaCry" cyberattack.
Britain's foreign office said on Tuesday that its National Cyber Security Centre had assessed it was highly likely that North Korea's Lazarus hacking group was behind the one of the most significant cyber attacks to hit the UK in terms of scale of disruption.
"We condemn these actions and commit ourselves to working with all responsible states to combat destructive criminal use of cyber space," Foreign Office minister Tariq Ahmad said.
"The indiscriminate use of the WannaCry ransomware demonstrates North Korean actors using their cyber program to circumvent sanctions," Ahmad added.
Back in May, a third of Britain’s public hospitals were affected by the WannaCry virus, which spread through devices across the world and locked them in exchange for cash.
The ransomware attack hit up to 300,000 computers in 150 countries.
Some experts said at the time that they had detected signs of a possible North Korean links, saying the code used had been similar to past hacks attributed to Pyongyang.
North Korea has denounced allegation that Pyongyang has been involved in a global ransomware attack.
The country has already been under United Nations sanctions over its nuclear and missile programs.