On Sunday night, Microsoft blamed the U.S. spy agency that had originally developed software that allowed the ransomware attack to infect computers.

Det Ch Insp Douglas Grant, who heads up the PSNI cyber crime unit, said there is no evidence yet that the virus has infiltrated computer networks in Northern Ireland.

Officials say they're aware of those problems.

"The first thing to do to protect all the data is to frequently back up all the data on the computer system depending how much work you do".

The virus infected over 200,000 computers in 150 countries, locking the contents of their drives unless a ransom of $300 or $600 was paid in Bitcoin.

Dame Fiona and the Care Quality Commission wrote to the Health Secretary to highlight a "lack of understanding of security issues", according to the newspaper, and that "the external cyber threat is becoming a bigger consideration".

WannaCry exploits a Windows vulnerability patched in March by Microsoft.

Last Friday, stolen NSA malware was used to attack hospitals, universities, and businesses around the world, ultimately hitting hundreds of thousands of computers in more than 150 countries, including the US, reaching what Europol-Europe's leading police agency-described as an "unprecedented level". Security experts have discovered that the ransomware also uses NSA's DoublePulsar as the backdoor.

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It said: 'There were no infected computers in North East GP practices and the priority through this worldwide malware incident was to protect the NHS computer network, clinical systems and patient data - and this was done very successfully.

Around 45 NHS organisations in England and Scotland, including hospitals, family doctor surgeries, and health services, were hit in the cyber-attack which prevented doctors, nurses and staff from accessing vital patient information.

Experts are warning that even though the ransomware may not be spreading as quickly as it was on Friday, there are still many businesses that could be affected by WannaCry in the days to come.

The indiscriminate attack, which began on Friday, struck banks, hospitals and Government agencies, exploiting known vulnerabilities in old Microsoft computer operating systems.

Software giant Microsoft later hit out at the "widespread damage" caused by the cyberattack.

The government decided in 2015 to not extend a £5.5 million deal with Microsoft to extend IT support for Windows XP. "An equivalent scenario with conventional weapons would be the US military having some of its Tomahawk missiles stolen".

"It is important to note that the vast majority of NHS organizations report that they are running contemporary IT systems, which are commissioned depending on local need", the NHS said in a statement.