An international manhunt was well under way for the plotters behind the world's biggest-ever computer ransom assault.
The indiscriminate attack, which began Friday, struck banks, hospitals and government agencies in more than 150 countries, exploiting known vulnerabilities in old Microsoft computer operating systems.
US package delivery giant FedEx, European car factories, Spanish telecoms giant Telefonica, Britain's health service and Germany's Deutsche Bahn rail network were among those hit.
Europol executive director Rob Wainwright said the situation could worsen on Monday when workers return to their offices after the weekend and log on.
"We've never seen anything like this," the head of the European Union's policing agency told Britain's ITV television, calling its reach "unprecedented".
"The latest count is over 200,000 victims in at least 150 countries. Many of those victims will be businesses, including large corporations.
"We're in the face of an escalating threat.
"I'm worried about how the numbers will continue to grow when people go to work and turn on their machines on Monday."
The warning was echoed by Britain's National Cyber Security Centre: "As a new working week begins it is likely, in the UK and elsewhere, that further cases of ransomware may come to light, possibly at a significant scale."
The 5,500-strong Renault factory in Douai, northern France, one of the most important car plants in the country, will not open on Monday due to the attack, sources told AFP.
