France’s government is moving quickly to mobilise the country’s top media execs in the wake of terror group ISIS’ hacking of TV5 Monde. French minister of culture Fleur Pellerin said she wanted to bring together all the heads France’s top TV companies as well as newspaper groups and the news agency Agence France-Presse within 24 hours to tackle any potential vulnerability to future cyber attacks.

Late Wednesday night, TV5 Monde’s broadcast was blacked out for a few hours and its Facebook and website was hacked by a group claiming allegiance to ISIS.  Amongst the documents purportedly posted  on TV5Monde’s Facebook page by the hackers were identity cards and CVs of relatives of French soldiers involved in anti-Isis operations.

“Soldiers of France, stay away from the Islamic State! You have the chance to save your families, take advantage of it,” read one message on TV5Monde’s Facebook page. “The CyberCaliphate continues its cyberjihad against the enemies of Islamic State,” continued the statement, which also included threats against French President Francois Hollande and references to the attacks in January on the Charlie Hebdo Paris headquarters and Hyper Cache supermarket that left 17 people dead over three days.

TV5 Monde execs were able to retrieve control of its social networks by Thursday morning, but warned it could be days before its TV broadcasts were fully operational again.

“When you work in television and you hear that your 11 channels have been blacked out, it’s one of the most violent things that can happen to you. At the moment, we’re trying to analyse what happened: how this very powerful cyber-attack could happen when we have extremely powerful and certified firewalls.”,” TV5 Monde boss Yves Bigot told AFP.

ISIS has developed a potent network of hackers and activists across social media, working simultaneously to attract potential new recruits as well as target and embarrass established websites of governmental and media agencies.  Earlier this week, ISIS-affiliated hackers seized control of the website of Defra, the UK government’s official air-quality agency, to post a message criticising Britain for its role in the invasion of Iraq in 2003. In January, ISIS hackers briefly seized control of U.S. Central Command’s Twitter and YouTube accounts.

The terrorist group has also found itself a target. Hactivist group Anonymous, previously better known for its coordinated hack attacks on government, religious and corporate websites, declared war on the social networks and media operations of terrorist organizations such as Al Qaeda and ISIS following the Charlie Hebdo attacks. Anonymous launched #OpIsis as a means to fight back against the terrorist group. It most recently published a list of 9200 ISIS supporters’ Twitter accounts and websites.

France’s Prime Minister Manuel Valls tweeted that the attack on TV5  Monde was “an unacceptable insult to freedom of information and expression”.

TV5 Monde broadcasts French language programming from Belgium, Canada, France and Switzerland around the world. It is 51% owned by a consortium comprised of France Télévisions, Arte France, Institut national de l’audiovisuel, Radio-Canada, Télé-Québec, RTBF and RTS. The remaining 49% is owned by France Medias Monde, a holding company that manages France’s international broadcasting services.