Anonymous hacktivists have promised to target the UK Home Office as a part of a wider anti-extradition protest to support Chris Tappin, Richard O'Dwyer and Gary McKinnon.
Rallying under the "Op Trial At Home" banner the call to arms stemmed from several Twitter accounts associated with the Anonymous collective.
All three are UK citizens accused of various crimes within the US including those relating to hacking and copyright infringement, and each could face lengthy jail sentences.
Already extradited, Tappin stands accused of illegally selling and sending air defence batteries to Iran.
Though the exact nature of the attack was not detailed, the statement gave the Home Office's IP address and website alongside a request that supporters "charge their lasers", indicating it will likely be a distributed denial of service attack (DDoS).
The news comes just after another cell of Anonymous made a similar threat to the Home Office over its web and email surveillance plans.
Set to be unveiled in May, it is feared the new legislation will let authorities monitor and track web users' browsing habits, email conversations and phone calls.
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