WASHINGTON/FRANKFURT (Reuters) - Officials across the globe scrambled over the weekend to catch the culprits behind a massive ransomware worm that disrupted operations at car factories, hospitals, shops and schools, while Microsoft on Sunday pinned blame on the U.S. government for not disclosing more software vulnerabilities.

Cyber security experts said the spread of the worm dubbed WannaCry - "ransomware" that locked up more than 200,000 computers in more than 150 countries - had slowed but that the respite might only be brief amid fears it could cause new havoc on Monday when employees return to work.

New versions of the worm are expected, they said, and the extent - and economic cost - of the damage from Friday's attack were unclear.

In a blog post late Sunday, Microsoft President Brad Smith appeared to tacitly acknowledge what researchers had already widely concluded: The ransomware attack leveraged a hacking tool, built by the U.S. National Security Agency, that leaked online in April.



More disruptions feared from cyber attack; Microsoft slams government secrecy