Microsoft is angry with America's National Security Agency (NSA). Microsoft said the WannaCry ransomware cyber-attack was because the NSA keeps cyber-weapons on its computers. Ransomware is a harmful software that blocks access to computers until the owner pays money (a ransom) to the hackers. The NSA is a military intelligence organization. It helps America's communications and information systems to stay safe. It also stops cyber-attacks against the USA. However, experts say the WannaCry ransomware used spying tools that were designed by the NSA.

Microsoft said governments must wake up to the problem of storing cyber-weapons. It said hackers can steal them and it was as dangerous as stealing missiles. Microsoft's president said: "This attack provides yet another example of why [governments keeping these things]…is such a problem." Europe's police agency said WannaCry has affected 200,000 computers in 150 countries. It made many problems for Britain's National Health Service. Many operations were cancelled. Experts warned people to back up their files because more attacks could come.