Hacker crew Team Poison has threatened to target the British authorities over the arrest of its leader, Trick, following the group's high-profile attack on MI6.
The group issued the warning via Twitter on Sunday, warning that it will fight back against the arrest of its members.
The group linked to a Pastebin statement with a call for other hackers to unite in attacking law enforcement agencies.
"We've lost the first and most important member of our team; our founder, our brother, our family member. Most importantly we lost a fighter for freedom, a fighter against corruption," it said.
"I ask you, a fellow hacker, as a blackhat, to rise, to unite and to fight."
Team Poison's ringleader, Trick, was arrested at the end of last week following a number of attacks, including the group's recent prank call assault on a police terrorism hotline.
The attack saw the group target MI6's phone service, overwhelming it with it a flood of automated prank phone calls.
Following the attack police confirmed arresting two suspects, aged 16 and 17, while not giving the individuals' names, one of the two was listed as being the group's leader Trick.
Speaking to V3, F-Secure analyst Sean Sullivan stated that Trick's arrest was indicative of a wider problem among young hackers who appear unaware their actions can land them in serious trouble with law enforcement agencies.
"There appears to be very little buffers allowing children to fail online in small and repairable way," he said.
"From those fighting copyright issues such as Richard O'Dwyer, to LulzSec hackers such as Jake Davis, the stereotypical hacker story from the UK is evolving to be that of a ‘quiet boy' doing things on his computer, in his room, that his parents have no clue or knowledge about."
Additionally, Sullivan suggested law enforcement's current tactics of simply arresting the young offenders, hoping to deter other youths from joining hacker groups, remains ineffective.
"Unfortunately, based on their PasteBay post, the rest of TeaMp0isoN appears to be doubling down on their misguided course," said Sullivan.
Team Poison is a group of hackers affiliated with the larger Anonymous collective. In the past, as well as the attack on the anti-terrorism hotline the group is believed to have been involved in several Anonymous led campaigns, including the high-profile attack on Stratfor in late 2011.