A reporter from the Health Service Journal said the attack had affected X-ray imaging systems, pathology test results, phone systems and patient administration systems.
"Hackers will realise that hospitals can be hacked relatively easily, and of course that hospitals have very sensitive data and we need that to manage our patients and it's time-critical data".
Hospitals and health clinics across England and Scotland battled to bring their computer systems back online Saturday after being paralyzed by a global ransomware attack.
A ransomware program called WannaCry infects computers and then locks them, demanding $300 in bitcoins to unlock them.
He said Russian Federation and India were hit particularly hard, largely because Microsoft's Windows XP - one of the operating systems most at risk - was still widely used there.
Several British hospitals were hit by a cyber attack on Friday, the country's National Health Service said, forcing some to divert ambulances to other clinics and urge people not to contact their doctors.
NHS Digital, the company that oversees Britain's hospital cyber security, said the attack used the Wanna Decryptor variant of malware.
There is no evidence patient data has been compromised, NHS Digital has said. "We will continue to work with affected (organizations) to confirm this".
The ransomware has hit hospitals in London, Blackburn, Nottingham, Cumbria and Hertfordshire, according to the BBC.
Nevertheless, the attack hit 48 NHS Trusts, and a number are still affected, including London's Barts Health NHS Trust, which runs The Royal London Hospital, Newham Hospital, Whipps Cross Hospital, Mile End Hospital and St Bartholomew's Hospital.
"The NHS was not particularly targeted".
There's no word yet as to whether this attack has spread to computers in South Africa.
Europol said its cybercrime specialists will support affected countries as a "complex global investigation" to identify the culprits begins. CNN has not independently confirmed that number.
The government's emergency council known as the Cobra committee was scheduled to meet Saturday to discuss the situation.
Telecommunications giant Telefonica was among the targets in Spain, though it said the attack was limited to some computers on an internal network and had not affected clients or services.
London's Barts Health NHS Trust, the largest trust in the United Kingdom, cancelled all outpatient appointments at its five hospitals on Saturday.
In his first public comments since the attack on Friday, Mr Hunt told Sky News: "Although we have never seen anything on this scale when it comes to ransomware attacks, they are relatively common and there are things that you can do, that everyone can do, all of us can do, to protect ourselves against them".
The most worrying development concerned problems with the hospital's referral system, Sean said. The program recommends certain patients for treatment with specialists and has a two-week availability window before the treatment is canceled.
"Nobody underestimates the difficulty of dealing with cyberattacks", Rudd said. Patients were asked not to go to hospitals unless it was an emergency and even some key services like chemotherapy were canceled.
And that's not the worst of it.
Mikko Hypponen, chief research officer at the Helsinki-based cyber security company F-Secure, told AFP it was the biggest ransomware outbreak in history, saying that 130,000 systems in more than 100 countries had been affected.
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