"We've never seen anything like this", the head of the European Union's policing agency told Britain's ITV television Sunday. But that number has nearly certainly risen as people in Asia - who had logged off for the workweek before WannaCry began spreading - have returned to work. Pictures posted on social media showed screens of NHS computers with images demanding payment of $300 (275 euros) in Bitcoin, saying: "Ooops, your files have been encrypted!"
"Our priority has been to restore our radiology services, and like other Trusts affected working with NHS Digital, we will continue to do all we can to protect our systems for the future". "The NHS has been lucky this time but it needs to take stock of where it's at", he said. But UK hospitals, Chinese universities and global firms like Fedex also reported they had come under assault. The ransomware was created to repeatedly contact an unregistered domain in its code. If you're running the most recent version of Windows, or XP with the appropriate security patches, you should be okay (though you should really stop using XP right away). Copycat attacks could follow.
But is the public sector really any worse than the private sector at keeping its IT security up to date and avoiding cybercrime?
"We haven't fully dodged this bullet at all until we're patched against the vulnerability itself", Kalember said.
Europol's Wainwright underscored the point Sunday. Security experts have strongly recommended all Windows users fully update their system with the latest available patches.
She added: 'Because GP practices do not operate on just one system, there is local variation in the support and advice being offered to GPs, but some CCGs have issued guidance and are updating GPs directly via text message.
The indiscriminate attack began Friday and struck banks, hospitals and government agencies, exploiting known vulnerabilities in older Microsoft computer operating systems. Some have also been machines involved in manufacturing or hospital functions, hard to patch without disrupting operations.
"Expect to hear a lot more about this [today] when users are back in their offices and might fall for phishing emails" or other as yet unconfirmed ways the worm may propagate, said Christian Karam, a Singapore-based security researcher.
It's still unclear who is responsible for the attack and speculations have pointed towards Shadow Brokers - who are also responsible for releasing the malware online - or multiple hacking organisations. Wainwright said Europol did not know the motive.
Given the attack's widespread nature, even such a small sum would stack up quickly, though few victims seem to be paying up so far.
WannaCry has already caused massive disruption around the globe.
People are advised to attend any hospital or doctor appointments as normal, unless they are contacted and told not to.
The effects were felt across the globe, with Britain's National Health Service, Russia's Interior Ministry and companies including Spain's Telefonica, FedEx Corp.in the US and French carmaker Renault all reporting disruptions.
The number of ransomware-affected cases is still rising.
In Russia, state-controlled media blamed USA secret services.
Scores of organisations inside the NHS, which provides free medical care for all and is a source of pride for Britons, were hit by the ransomware on Friday. The malware's name is WCry, but analysts were also using variants such as WannaCry.
Russia's Interior Ministry acknowledged a ransomware attack on its computers.