Many security firms are already aware of WannaCry in past forms and most are looking at this one right now to see how it might be stopped.
The NHS says that it is working closely with the National Cyber Security Centre, The Department of Health, and NHS England to both support affected organizations and ensure patient safety.
The Barts Health group, which manages major central London hospitals including The Royal London and St Bartholomew's, said it had activated a major incident plan and had cancelled routine appointments.
The National Health Service (NHS) in the United Kingdom has confirmed that 16 different NHS organizations have been affected by the brand-new Wanna Decryptor 2.0 ransomware-while it has emerged that the campaign is global and coordinated, with tens of thousands of attacks on various sectors in just the last few hours.
In a statement to NBC News, FedEx said that "like many other companies, FedEx is experiencing interference with some of our Windows-based systems caused by malware".
Similar widespread attacks have been reported in Spain and other countries.
Writing in the British Medical Journal, he said: "We should be prepared: more hospitals will nearly certainly be shut down by ransomware this year".
In a statement from the NHS Merseyside's information management and technology services, the trust said there had been a "suspected national cyberattack".
On Friday in Britain, pictures of NHS computer screens were featured on social media.
Health workers reported being locked out of their systems and seeing messages demanding ransom payments to regain access.
"It's not hard to remove, but it also doesn't seem to be decryptable", Abrams said.
The malware that has affected the NHS England hospitals is also hitting people and companies across Europe and Asia, according to experts.
"Ambulances are being diverted to neighbouring hospitals", it said.
It said, the investigation is at an early stage and the malware variant could be Wanna Decryptor.
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.
The hackers are demanding payment of 300 USA dollars worth of the online currency Bitcoin, after NHS computers saw a message pop up saying: "Ooops, your files have been encrypted!"
"Currently, we have recorded more than 45,000 attacks of the WannaCry ransomware in 74 countries around the world, mostly in Russian Federation", cyber security firm Kaspersky says.
Spain's National Cryptologic Center, which is part of the country's intelligence agency, said on its website that there had been a "massive ransomware attack" against a large number of Spanish organizations affecting Microsoft'sWindows operating system.