An NHS Digital statement said: "NHS Digital is working closely with the National Cyber Security Centre, the Department of Health and NHS England to support affected organisations and ensure patient safety is protected".
Tens of thousands of ransomware attacks Friday targeted organizations around the world, including 16 that are part of the National Health Service.
"The fact that so many organizations were vulnerable to this was quite a surprise", cyber expert and CEO of Capital Alpha Security in the U.K. Matt Tait told NPR.
South Korea's Yonhap news agency reported a university hospital had been affected, while a communications official in Indonesia said two hospitals there had been affected. "Believed to be affecting only Windows operated computers, it changes the affected file extension names to ".WNCRY".
Production at Nissan's manufacturing plant in Sunderland, northeast England, has been affected by a cyber attack that has hit almost 100 countries, a spokesman for the Japanese carmaker said on Saturday, May 13, Reuters reports.
"We are aware that a number of NHS organizations have reported they have suffered from a ransomware attack", May said while out on the campaign trail in the UK.
"Known as WannaCry or Wanna Decryptor, the so-called ransomware programme homes in on vulnerabilities in Microsoft Windows systems", the daily said.
"It's unequivocally scary", said John Dickson of the Denim Group, a U.S. security consultancy.
It encrypts files on a user's computer, blocking them from view, before demanding money, via an on-screen message, to access them again.More news: Tropico dev goes to space with Surviving Mars
More news: New system changed Chelsea's season, claims Premier League champion Conte
More news: Delhi gas leakage : 85 school students hospitalised
Britain's opposition Labour Party said the attack on English hospitals showed the need to place cyber security at the heart of government policy.
Germany's Deutsche Bahn computers were also impacted, with the rail operator reporting that station display panels were affected.
"It had a countdown clock ticking down, stating that all data would be deleted unless a payment was received within that timeframe", he said.
The hackers, who have not come forward to claim responsibility or otherwise been identified, likely made it a "worm", or self spreading malware, by exploiting a piece of NSA code known as "Eternal Blue" that was released last month by a group known as the Shadow Brokers, researchers with several private cyber security firms said.
Although Microsoft released a security patch for the flaw earlier this year, many systems have yet to be updated, researchers said. In February 2016, a Los Angeles hospital, the Hollywood Presbyterian Medical Center, paid US$17,000 in Bitcoin to hackers who took control of its computers for more than a week.
In a matter of hours, over 75,000 attacks have been detected worldwide, the company said.
"Ransomware becomes particularly nasty when it infects institutions like hospitals, where it can put people's lives in danger", said Kroustek, the Avast analyst.
Among them was the Barts Health group which manages major central London hospitals including The Royal London and St Bartholomew's. "Ambulances are being diverted to neighbouring hospitals", the statement says.
Alan Woodward, visiting professor of computing at the University of Surrey, said there was evidence the ransomware was spreading using a Microsoft flaw exposed in a recent leak of information from US intelligence agencies.