The cyberattacks started Friday and spread rapidly around the globe using a security flaw in Microsoft's Windows XP operating system, an older version that is no longer given mainstream tech support by the USA giant.
Other high-profile victims include hospitals in Britain, Spanish telecoms giant Telefonica, French vehicle maker Renault, US package delivery company FedEx, Russia's interior ministry and the German rail operator Deutsche Bahn.
"The numbers are still going up", he said.
In a statement this afternoon, chief operating officer Mark Brassington said the trust was still involved in a "major incident" and urged people to use accident and emergency wisely: "Significant progress has been made in restoring our IT systems following the cyber attack that hit our hospitals on Friday".
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.
Alex Abdo, a staff attorney at the Knight First Amendment Institute at Columbia University, said Microsoft and other software companies have strategically settled lawsuits that could lead to court rulings weakening their licensing agreements.
The global attack could have been far worse if not for a pair of cybersecurity researchers, including Darien Huss, from MI, who stumbled on a kill switch hidden in the domain name the hackers were using. That move, which cost just $10.69, redirected the attacks to the server of Kryptos Logic, the security company where he works.
"It's quite an easy change to make, to bypass the way we stopped it", he told the AP. A malware researcher in the United Kingdom. "We can't drop our guard", said a Sabadell spokesman. If not, update right away.
FedEx: The company said this weekend it was "experiencing interference with some of our Windows-based systems caused by malware" and was trying to fix the problems as quickly as possible.
"Whether or not you think the USA government should be spending a fortune developing such cyberweapons, surely it is obvious that the weapons they develop should be properly secured". Until the public's knowledge of their tools catches up to the frequency with which they use them, attacks on the scale of the WannaCry outburst have the potential to be duplicated more frequently than you'd care to think about.
But experts and government alike warn against ceding to the hackers' demands.
WannaCry exploits a Windows vulnerability patched in March by Microsoft. One did not include the so-called kill switch that allowed researchers to interrupt the malware's spread Friday by diverting it to a dead end on the Internet.
President Donald J. Trump has ordered his homeland security adviser, Thomas P. Bossert, who has a background in cyber issues, to coordinate the government's response to the spread of the malware and help organize the search for who was responsible, an administration official said on Sunday.
But for many systems, especially older systems, such patches are not installed automatically-a fact the hackers took advantage of.
French carmaker Renault said its Douai plant, one of its biggest sites in France employing 5,500 people, would be shut on Monday as systems were upgraded. If they're not paid, the files get destroyed.
There were 213,000 infected machines in 112 countries as of 1000 GMT today, according to Czech security firm Avast, making it one of the largest coordinated attacks to hit computers across the world.
British cybersecurity expert Graham Cluley doesn't want to blame the NSA for the attack.
Liz Capp-Gray, acting director of health informatics at Medway Foundation Trust, said: "I can confirm that we have not, so far, been directly targeted by the WannaCry ransomware attack".
Microsoft's top lawyer is laying some of the blame at the feet of the US government.
He said most people "are living an online life", and these agencies have a duty to protect their countries' citizens in that realm as well. Because they can be used against you.