WannaCry: The cyber-attack on Friday has affected more than 200.000 people in 150 countries, Europol chief Rob Wainwright told the BBC. He went on to say that the hack was "unprecedented in scale" and warned that more people could be among the victims on Monday morning.
Ransomware continues to encrypt its victims' records, requiring payments. Russia and the United Kingdom were among the countries most affected.
Experts say another attack could take place and warn the public to update their systems. Mr Wainwright, head of the European Union's law enforcement service, said ransomware used a worm-like application in addition to infecting the computer, allowing it to "spread quickly across all networks".
He added: "This is why we see these numbers constantly increasing."
Although a temporary fix (the kill switch domain of MalwareTech) had slowed down the infection rate earlier, the attackers released a new version of the ransomware, he said.
Businesses need to make sure they have updated their systems and "fix the things they should have fixed" before their staff came to work Monday morning, Rob Wainwright said.
In England, 48 National Health Service (NHS) (from the National Health Service) reported problems in hospitals, GP surgeries or pharmacies and in 13 NHS services in Scotland.
What happened was an "indiscriminate attack on multiple industries and services," Wainwright said, including the German rail network Deutsche Bahn, the Spanish telecommunications company Telefonica, the US logistics company FedEx and the Russian Interior Ministry.
However, he said that so far few payments have been made "remarkably" by the victims of the attack.
According to the BBC hackers have received £ 22,080 from England.
The head of Europol said his agency is working with the US Federal Bureau of Investigation (FBI) to find those responsible and that more than one person is likely to be involved.
Recall that the virus exploits a vulnerability in Microsoft Windows software, which was first detected by the US NSA.
After a successful infection, it displays messages that require a $ 300 (or £ 230) payment to the Bitcoin virtual currency to unlock the files and be able to use the victim again.
Microsoft released security updates last month to address vulnerability, but it also released an update yesterday for systems that no longer support it.
What is to be done in the next few days:
The security researcher "MalwareTech", who helped limiting the WannaCry ransomware attack, already predicted "another one to come… probably on Monday". MalwareTech's statement has a basis, as Europol's Rob Wainwright said the attackers had released a new version of ransomware.
22er who wants to remain anonymous told the BBC that it is very important for everyone to update their systems as soon as possible.