Beijing: North Korea's state newspaper has acknowledged that the world was "astonished" by the "unprecedented attack" of the WannaCry computer worm.

Amid speculation that North Korean hackers could have been behind the computer worm, the Rodong Sinmun newspaper on Wednesday reported the wide scale of the chaos WannaCry had caused. 

Banks, health care and IT organisations in 150 countries had been hit as 200,000 computers were impacted, it informed North Korean readers, who are isolated from the internet.

But while appearing to take a triumphant tone, the newspaper stopped short of claiming North Korean responsibility.

A "simultaneous cyber attack" worldwide by the "vicious virus" had caused deep concern in international society, it said. 

"International society couldn't help be astonished at the unprecedented cyber attack, in terms scale and damage, and called for strengthened efforts to prevent crimes in cyber space," the report ended. 

How the WannaCry malware works.

It has been suggested in the United States that the worm shared a segment of code known to have been used in the past by a North Korean-linked hacking group.

A Centre for Strategic and International Studies report in August highlighted that North Korea operated a cyber warfare unit of 3000 elite hackers called Unit or Bureau 121, who has broken into systems and spread viruses.

"Cyber warfare is asymmetrically advantageous for the DPRK. As the country is almost entirely not connected to the internet, it is much less exposed to such attacks," wrote the centre's Anthony Cordesman.

Chinese state media instead blamed the United States, and said it was "hypocritical" for the US to accuse China of state-sponsored cyber espionage.

In an editorial, the official mouthpiece China Daily said 30,000 institutions in China, including universities and petrol stations, fell victim to WannaCry.

The US National Security Agency "must shoulder some of the blame" because the one of its hacking tools had ended up in the hands of hackers, the editorial argued.

The claim that WannaCry used elements stolen from the NSA was first made by Microsoft President Brad Smith, and the US Government has not responded to the claim.

The virus locks computers and demands a ransom be paid to unlock files.

Three computer security companies, Symantec, Kapersky and Hauri, have said the WannaCry software appears to share code used by hacking groups linked to North Korea which attacked South Korean banks, TV stations and Sony in the past. However, they cautioned they needed to study the code further before concluding North Korea was to blame.