Massive ransomware attack strikes 99 countries

A large scale ransomware attack using tools stolen from the US National Security Agency has struck 99 countries this morning.

The huge attack, which spread across the world, has infected computers in the US, Europe and Asia.

Computers in thousands of locations have been locked by the malicious software which demands a payment of $300 in Bitcoin to restore access. The ransom will rise with time and the files will eventually be deleted, the warning reads.

On Friday night, US firm Fedex announced its operations in the US were affected. Russia's interior and emergencies ministries, as well as the country's biggest bank, Sberbank, confirmed they had been targeted.

A number of Spanish firms - including telecoms giant Telefonica, power firm Iberdrola and utility provider Gas Natural – were also affected by the the malware attack. Portugal Telecom, delivery company FedEx, a Swedish local authority and Russia's second largest mobile phone network, Megafon, also announced that they were affected.

People took to Twitter to share photos of affected computers including a local railway ticket machine in Germany and a university computer lab in Italy.

Some reports said Russia had seen more infections than any other single country. Russia's interior ministry is reported as saying it had "localised the virus" following an "attack on personal computers using Windows operating system".

In April hackers known as The Shadow Brokers claimed to have stolen the tools from the NSA and released them online.

Microsoft released a patch for the vulnerability in March, but many machines and older operating systems may not have been updated.

99 countries have reported infections, including the UK, US, China, Russia, Spain, Italy and Taiwan. Cyber-security firm Avast is reported as saying that it had seen 75,000 cases of the ransomware - known as WannaCry and variants of that name - around the world.

The attack wrought havoc with the UK's National Health Service as dozens of hospital trusts across the country were forced to turn off their computer systems.

Emergency patients in are reportedly being diverted to other areas, with hospitals across England and Scotland affected. Affected NHS trusts said that IT systems had been shut down in order to protect them. That meant that all systems were offline and hospitals were unable to accept incoming calls.

The attack on comes not long after a report was published in the British Medical Journal in which neurologist Dr Krishna Chinthapalli warned that hospitals were at risk of a cyber attack. "We should be prepared: more hospitals will almost certainly be shut down by ransomware this year," he wrote.

In a statement,Downing street said there was no evidence that patient data had been compromised.