Friday's cyber attack hit 200,000 victims in at least 150 countries, the head of the European Union's police agency said on Sunday, adding he feared that number would grow when people return to work on Monday.
Europol Director Rob Wainwright told ITV's Peston on Sunday programme that what was unique about the attack was that the ransomware was used in combination with "a worm functionality" so the infection spread automatically.
"The global reach is unprecedented. The latest count is over 200,000 victims in at least 150 countries, and those victims, many of those will be businesses, including large corporations," he said.
"At the moment, we are in the face of an escalating threat. The numbers are going up, I am worried about how the numbers will continue to grow when people go to work and turn (on) their machines on Monday morning."