The Anonymous hackers collective is preparing to unleash a fresh wave of cyberattacks on Islamic State, following the attacks in Paris last week that killed 129 people, it said in a video posted online.
In a video uploaded onto a social media website on Saturday, a man wearing a Guy Fawkes mask said the Islamic State militants who claimed responsibility for the Paris attacks were "vermin" and Anonymous would hunt them down.
"Yesterday, Friday November 13th 2015, our country, France was attacked in Paris at around 10 pm by multiple terrorists attempts claimed by you, ISIS (Islamic State). These attacks cannot remained unpunished, hence the reason why the anonymous from all over the world will hunt you down, yes you vermin that are killing innocent people, we will hunt you down, as we did since the attacks of Charlie Hebdo," the man said in the video, speaking in French.
Since the attack on French weekly Charlie Hebdo last January, which led to the deaths of 17 victims, Anonymous activists have waged an online vigilante campaign to force the shutdown of Twitter profiles suspected of belonging to IS supporters.
"Therefore, be prepared for a massive retaliation from the Anonymous. Be advised that we will find you and will not let you go; we are going to launch the biggest operation ever against you. Expect many cyberattacks. War has been declared. Get ready," the man said, without giving details of what the attacks would involve.
"The French people are stronger than you and will come out of this atrocity even stronger. Anonymous presents its condolences to the family of all the fallen victims. We are the Anonymous, we are legion. We don't forgive and we don't forget. Expect us," he added.
Anonymous is an international network of activist computer hackers which has claimed responsibility for many cyberattacks.
The video posted to YouTube had attracted more than 1.1 million views by 2.30pm GMT yesterday.
The group says it has identified more than 39,000 suspected IS profiles and reported them to Twitter.
It claims to have had more than 25,000 of these accounts suspended, while nearly 14,000 more on the targeted list remain active, according to a list posted to a site calling itself Lucky Troll Club.