Pledged to close jihadi social network accounts to avenge those murdered

Anonymous has now released a video 'declaring war' against terrorists

The hacking group have condemned the Paris massacre which killed 12

Hacking group Anonymous has 'declared war on jihadists' in the wake of the Charlie Hebdo massacre in Paris.

Authorities targeting extremists may have found an unlikely ally in the group in the battle against terrorism after the activists released a video condemning the gun attack at the satirical magazine which left 12 people dead.

In the clip, which was uploaded to the group's Belgian YouTube account, a figure wearing the group's Guy Fawkes mask and a hood says in French in an electronically-distorted voice: 'We are declaring war against you, the terrorists.'

Hacker group Anonymous (pictured) has declared war on jihadists after the tragic massacre in Paris this week

Sitting at a desk and reading from a piece of paper, the figure says the group will track down and close all accounts on social networks related to terrorists to avenge those killed.

The hashtag #OpChalieHebdo - presumably meaning Operation Charlie Hebdo - also appears on screen.

The group also reportedly published a statement on text-sharing website Pastebin, entitled 'Message to the enemies of freedom of expression'.

The hackers have threatened to target terrorists online after two armed gunmen stormed the Charlie Hebdo offices killing a dozen people (pictured)

In it they wrote: 'Freedom of expression has suffered inhuman assault ... It is our duty to react ... We wish to express our condolences to the families of the victims of this cowardly and despicable act.'

They added: 'We will fight always and everywhere the enemies of freedom of expression ... Freedom of expression and opinion is a non-negotiable thing. To tackle it is to attack democracy.

'Expect a massive frontal reaction from us because the struggle for the defense of those freedoms is the foundation of our movement.'

Anonymous has previously carried out cyber attacks on websites belonging to the Government, as well as those of corporate and religious organisations.

In 2012 Anonymous crippled the Home Office's website by flooding it with huge amounts of internet traffic.