North Korea-linked Lazarus Group may be behind global cyber-attack that has affected thousands of computers and disrupted hospitals, schools and assembly plants in some countries.

This is according to Cyber firms Symantec, Kaspersky, who said they are looking into technical clues that suggest that the global attack came from the North Korea-linked  group.

The  global “ransomware” attack, also known as WannaCry had programs previously attributed to North Korea, the computer security firms said.

The two companies said some code in an earlier version of the WannaCry ransomware, which has encrypted data on hundreds of thousands of computers since Friday, and demanded users pay money to regain control of their machines, had also appeared in programs used by the Lazarus Group, which researchers from many companies said is run by North Korea.

Reuters reported that  North Korean mission to the United Nations was not immediately available for comment.