In a sinister video posted on YouTube, the fearless cyber activists said they will launch their "biggest operation ever" - warning the depraved terror group to "expect us".

Behind their trademark Guy Fawkes mask, a spokesman said: "Anonymous from all over the world will hunt you down. You should know that we will find you and we will not let you go.

"We will launch the biggest operation ever against you."

The masked man told the savage terrorists to expect "massive" cyber attacks, adding: "War is declared. Get prepared.

"The French people are stronger than you and will come out of this atrocity even stronger."

After the Charlie Hebdo attacks in January, Anonymous started publishing a list of Twitter accounts it says are spreading Islamic State propaganda.

Over the weekend ISIS claimed responsibility for the latest attacks in Paris which have so far claimed the lives of 129 people.

The terrorists targeted six different locations in the French capital, including Stade de France where president Francois Hollande was watching the national team play a friendly match against Germany.

Gunmen also attacked restaurants and cafes where people were enjoying a night out.

Most of the victims came from the Bataclan theatre where rock band Eagles of Death Metal were performing when gunmen burst into the concert hall and fired into the crowd.

89 people were killed there - and there are still 26 victims yet to be identified, while a further 99 people are critically injured following the bomb and gun attacks.

Among the victims is Briton Nick Alexander who was selling band merchandise at the Bataclan gig.

The 36-year-old's girlfriend of three years Polina Buckley posted an emotional tribute on social media following his death.

She said: "Three years ago on this day I met you on the corner of East 15th and Irving Pl. I fell in love the moment I laid eyes on you.

"This was the most loving, passionate and eventful relationship I've ever experienced. You were my everything. My lover, my best friend, my soulmate."

Mr Alexander was believed to have been protecting another person when he was killed.

Speaking to Sky News, former colleague Lauren Roth De Wolf said: "What I heard is that he died saving the life of another human being.

"And that's, I think, the act that all of us wonder if we'd be brave enough to do.

"It's tragic but also awe-inspiring. I don't know if anybody knows if they'd be strong enough to do that until it happens."

French officials have named four of the suicide bombers in Friday's attack.

Ibrahim Abdeslam, a 31-year-old Belgian national, blew himself up outside outside the Comptoir Voltaire restaurant.

His brother Salah Abdeslam, 26, is wanted by French police but it is not known whether he is dead or alive

Officials also named French national Omar Ismail Mostefai, 29, as an attacker after identifying him from a severed finger among the carnage at the Bataclan concert hall.

A third jihadi was Ahmed Almuhamed, a Syrian who reportedly arrived in Greece on a refugee boat.

Bilal Hadfi, also from Belgium, is the fourth attacker identified by authorities.

Courtesy Express