The activist hacker network Anonymous said it is preparing to unleash waves of cyber attacks on the Islamic State group, following the attacks that killed 129 people last week in Paris.
In an unverified video posted on YouTube, a spokesperson wearing the group's signature Guy Fawkes mask said the loose-knit international group would use its expertise to wage "war" on the militants who claimed responsibility for the Paris attacks.
"These attacks cannot remain unpunished," the man said, speaking in French.
Rise to prominence
The hacker group rose to prominence after a series of cyber attacks against individuals, governments and organizations that it does not approve of, including PayPal, Mastercard and the Church of Scientology, among others.
The Anonymous spokesman said it would be the group's biggest operation, "Expect many cyberattacks. War has been declared. Get ready," the man said, without giving details of what the attacks would involve. "We do not forgive and we do not forget."
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 ISIS supporters.
The group says it has identified more than 39,000 suspected ISIS profiles and reported them to Twitter. It claims to have had more than 25,000 of these accounts suspended. Nearly 14,000 more on the targeted list remain active, according to a list posted to a site calling itself Lucky Troll Club.