20 May, 2017
Wainwright added that what occurred was an indiscriminate attack across the world on multiple industries and services including Germany's rail network Deutsche Bahn, Spanish telecommunications operator Telefonica, US logistics giant FedEx and Russia's interior ministry.
Qihoo had previously said the attack had infected close to 30,000 organisations by Saturday evening, more than 4,000 of which were educational institutions.
"It started its assault against hospitals across the United Kingdom and shortly after spilled across the globe", the agency said.
"The global reach is unprecedented".
"At the moment, we are in the face of an escalating threat".
"I'm anxious about how the numbers will continue to grow when people go to work and turn on their machines on Monday", he said.
The attack looks like this: images appear on victims' screens demanding payment of $300 (275 euros) in the virtual currency Bitcoin, saying: "Ooops, your files have been encrypted!"
Payment is demanded within three days or the price is doubled and, if no payment is received within seven days, the locked files will be deleted, according to the screen message.
South Korea's presidential Blue House office said nine cases of ransomware were found in the country, but did not provide details on where the cyber attacks were discovered. "We have seen vulnerabilities stored by the Central Intelligence Agency show up on WikiLeaks, and now this vulnerability stolen from the NSA has affected customers around the world", Mr Smith wrote.
"The governments of the world should treat this attack as a wake up call".
In its latest update on the incident, Europol said it was the "largest ransomware attack observed in history".
The attack therefore spread faster than previous, smaller-scale ransomware attacks.
"It is important to note that the vast majority of NHS organisations report that they are running contemporary IT systems, which are commissioned depending on local need", the NHS said in a statement.
Cyber security experts in the National Health Service (NHS) worked alongside the National Cyber Security Centre (NCSC), part of the GCHQ spy agency, to patch computer systems after the attack caused widespread problems on Friday, Wallace said. "We are implementing remediation steps as quickly as possible".