European governments and companies appeared early Monday to have avoided further fallout from a crippling global cyberattack, the police agency Europol said.
"The number of victims appears not to have gone up and so far the situation seems stable in Europe, which is a success," senior spokesman for Europol, Jan Op Gen Oorth told AFP.
"It seems that a lot of internet security guys over the weekend did their homework and ran the security software updates."
Europol said more than 200,000 computers around the world had been affected over the weekend in what it said was "an unprecedented attack".
The indiscriminate attack began Friday and struck banks, hospitals and government agencies, exploiting known vulnerabilities in older Microsoft computer operating systems.
Europol executive director Rob Wainwright had warned on Sunday the situation could worsen when workers return to their offices on Monday after the weekend and logged on.
"We've never seen anything like this," the head of the European Union's policing agency told Britain's ITV television Sunday.
Op Gen Oorth said Monday it was still "a bit early too say who is behind it, but we are working on a decrypting tool".
Called "WannaCry," the fast-spreading malware is the first ever detected to combine both a worm—which enables it to burrow into an entire network from a single infected computer—and a ransomware, demanding $300 (275 euros) in the virtual currency Bitcoin to unlock systems.
Explore further: Growing global cyberattack hits 200,000 victims so far