Hackers have struck again as a new strain of ransomware, reportedly known as Petya, is sweeping across Europe taking computer systems of major corporations, ATMs and phone systems offline.

Ukraine, Russia, France and Spain have so far been confirmed as victims of the cyberattack, which is shutting down networks in demand for $300 worth of bitcoin, bearing striking similarity to the devastating WannaCry virus that crippled the NHS in May. However, it is reported it may spread further to the UK and possibly further afar to India.

Among the victims at this early stage involve banks, pharmaceutical companies, energy and transportation companies, shipping and financial services.

According to cybersecurity experts currently analysing the ransomware's internal code, it is believed the strain (being called GoldenEye by some experts) is being supercharged with the 'Eternal Blue' leaked NSA hacking tool, which is why the virus is able to spread so quickly and aggressively.

While the WannaCry virus was stopped thanks to an industrious IT engineer finding a 'killswitch' it appears no such feature is present with Petya. However, a vaccination has been found. Unlike WannaCry, Petya is also spread via email spam in the form of boobytrapped Office documents, according to at least one expert.

Kaspersky Lab cyber expert Costin Raiu tweeted the ransomware appeared to be "spreading worldwide" with a "large number of countries affected."

Below is a full list of companies and industries that have been affected by the Petya cyberattack so far (this will continue to be updated):

Chernobyl nuclear power plant: Radiation monitoring systems affected

Merck: The second-largest drugmaker in the United States

AP Moller-Maersk: Danish transport and energy company. Operations at a terminal at India's busiest container port in Mumbai have been stalled

Rosneft: Russian oil producer

Ukrenergo: Ukraine state-owned power company

Kyivenergo: Ukraine state-owned power company

Borispol Airport in Kiev, Ukraine

Oschadbank: Ukraine state-owned bank

Mondelez: American food and drinks giant

WPP: One of the world's largest advertising agencies, based in London

DLA Piper: Global law firm phones and computers down

Saint-Gobain: French material construction company

Ukraine metro system

Heritage Valley Beaver and Heritage Valley Sewickley hospitals: Care facilities in Pittsburgh, US.

Cadbury: Chocolate factory in Tasmania, Australia (owned by Mondelez)

Deutsche Post: German postal company

Evraz: Russian steelmaker

How the ransomware attack unfolded on Twitter:

Hacking