The site went offline ahead of the annual Victory Day parade on the Red Square in Moscow that came more than two months after Russia launched what it calls a 'special military operation' in Ukraine.

The outages also knocked offline some 5,800 wind turbines in Germany and Central Europe with a combined output of 11 gigawatts.

Britain and the US have warned of potential cyberattacks on Ukraine which could have international consequences.

The victims in Ukraine included a government agency and a financial institution, according to three people who studied the malware since its release.

Ukraine has previously accused Russia of launching cyberattacks to sow panic and crash its financial system.

Services were disrupted by a software update, not a cyberattack.

The US coordinated its statement with allies – the European Union, Britain, Australia, Canada, New Zealand, Japan and Nato.

The FBI has opened an investigation along with the Cybersecurity and Infrastructure Security Agency and other US federal agencies 'to understand the scope of the threat'.

The company reportedly paid the ransom in untraceable cryptocurrency.

Some 580,000 Singapore Airlines customers have had data compromised by a leak from an external air transport IT company.

A group calling itself 'Anonymous Malaysia' has threatened to carry out cyberattacks on government websites and online assets, saying authorities are ignoring data security.

So far officials have said the hackers broke into computers at the State Department, Commerce Department, Treasury, Homeland Security Department, and the National Institutes of Health.