SEOUL, South Korea, Dec 21:  North Korea said Thursday that a U.S. accusation that it was behind a major ransomware attack was a "grave political provocation" and vowed to retaliate.

WASHINGTON, Dec 19: President Donald Trump’s administration is publicly blaming North Korea for a ransomware attack that infected hundreds of thousands of computers worldwide in May and crippled parts of Britain’s National Health Service.

LONDON, May 14:  A global “ransomware” cyberattack, unprecedented in scale, had technicians scrambling to restore Britain’s crippled hospital network Saturday and secure the computers that run factories, banks, government agencies and transport systems in many other nations.

LONDON, May 12: A large cyberattack crippled computer systems at hospitals across England on Friday, with appointments canceled, phone lines down and patients turned away.