China and Japan has both announced they have fallen victim to the global "ransomeware" attack, which has caused complete chaos in 150 countries.
Experts were scrambling to determine who was behind the attack, which exploited a security flaw in older versions of Microsoft's Windows operating software. Russia's Interior Ministry and companies including Spain's Telefonica, FedEx Corp.in the USA and French carmaker Renault all reported troubles.
According to Xinhua, by Saturday night, 29,372 institutions had been infected along with hundreds of thousands of devices.
The Government Digital Service, established by David Cameron, failed to extend a £5.5 million one-year support deal with Microsoft, or to secure a replacement package. "The global reach is unprecedented", BBC quoted Wainwright as saying in an interview with Britain's ITV.
Wainwright described the cyberattack as an "escalating threat".
"I am anxious about how the numbers will continue to grow when people go to work and turn [on] their machines", Rob Wainwright, director of the European investigative agency Europol, told NBC News' U.K. partner ITV on Sunday.
"This means that as a new working week begins it is likely, in the United Kingdom and elsewhere, that further cases of ransomware may come to light, possibly at a significant scale", the NCSC said.
The cyber attack last week, which is known as WannaCry and demands Bitcoin payment in exhange for access to locked files, has affected 48 health organisations across England and Scotland, causing 16 to shut down their IT systems. The ransom demand would double after three days, following which all the encrypted files would be deleted if the users do not pay.
Bitcoin, the world's most-used virtual currency, allows anonymous transactions via heavily encrypted codes.
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.
"It's very likely that someone will reverse engineer this ransomware worm to generate an updated version, which you can guarantee will not contain a "kill switch". It uses all the same exploits as the WannaCry ransomware, including EternalBlue, a vulnerability first discovered by the NSA and leaked by the hacker group Shadow Brokers in April.
Brad Smith, Microsoft's president and chief legal officer, said yesterday in a blog post that his company, its customers and the government all share the blame, the report said.
"An equivalent scenario with conventional weapons would be the USA military having some of its Tomahawk missiles stolen".
In a statement on Sunday, Microsoft warned that the ransomware attack must be a "wake up call" to governments to update their systems.
Just one person in an organization who clicked on an infected attachment or bad link, would lead to all computers in a network becoming infected, said Vikram Thakur, technical director of Symantec Security Response.
It is the largest ransomware attack observed in history.
The attack grew over the weekend from 45,000 victim systems to an estimated 200,000, crippling large organisations from the NHS in the United Kingdom to Renault factories in France, Telefónica in Spain as well as Russia's second largest mobile operator, MegaFon.